User:MinorProphet/Draft subpages/man convert

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Posted by MinorProphet (talk) 10:58, 20 September 2015 (UTC)

This is an attempt to create a complete and inclusive Manual for {{convert}}. I think the need for such a manual exists, and I'm happy to have a go. Please let me know if I'm wasting my time, and in what way.

Purpose of this page[edit]

  1. To arrive at a consensus for a standard, meaningful, and consistent nomenclature for the {{Convert}} template and its documentation.
  2. To apply the nomenclature in a uniform style to a proposed manual, perhaps similar in style to:

or other similar approach suitable for adapting to {{convert}}.

Background[edit]

Having leaped in at the deep end by attempting to order the tables at Template:Convert/list of units, I have come to realise that the {{convert }} template is an unusually complex 1337 undertaking. I feel it could benefit greatly from a complete and inclusive manual along the lines of nixen man pages or the old MS-DOS 6.22 printed manual. I haven't really come across this idea in practice on WP or other MW operations. I have no axe to grind, as they say: absolutely no criticism is implied of anything or anyone. I may be trying to re-invent the wheel, or missing something vital on the road to Epic Fail. The talk page is open for comments.

I have a foolish(?) vision of a first-time user being able to use the template and the get the correct desired result first time, by working through a decent manual in which every unnamed and named parameter is comprehensively treated in full, with all the defaults and exceptions and mutually exclusive options/parameters/values/ and work-arounds and kludges explained and/or mouse-overed etc.

For example, every option could be arranged (in the order they occur as you fill/construct the template) in its own collapsed section, something like this empty demo:

Input options
Conversion-value {{convert|2|
Multiple conversion-values
Range-separators - by/x/to - formatted like List of Units {{convert|2|x|3|
Input unit-code, {{convert|2|x|3|kg involving:
List of units
unit-names
unit-symbols, etc.
Explanation of meaning of each column in List of Units
Output unit-codes {{convert|2|x|3|kg|lb
Multiple combination outputs etc. {{convert|2|x|3|kg|lb
Rounding-value {{convert|2|x|3|kg|lb|3
|sigfig=, |round= {{convert|2|x|3|kg|lb|sigfig=3
Output options
Explanation of left and right-hand sides of output, etc and all their wild combos.
abbr=
|abbr=out|in/on/off {{convert|2|x|3|kg|lb|sigfig=3|abbr=off
|abbr=out (default)
|abbr=in
|abbr=on
|abbr=off
adj=
|adj=in/out/shake_it_all_about
disp=
etc.

Mock-up of General outline of manual, based on the above list, cobbled together in under 2 minutes

I can't be alone in feeling that much of the template documentation on WP is frustratingly incomplete, having been perhaps written by and for the pizza-and-jolt-cola types who coded it in the first place. Pwnd. I have some experience in writing instructions user manuals, which is a different skill to coding.

In creating this page, I was partly prompted by the somewhat incomplete examples at Template:Convert. Although certainly helpful, I think that the page often only hints at the relatively complex task that awaits the unsuspecting standard user/WP editor (like me), with sub-standard logic or mathematical abilities. Sometimes section headings are hardly addressed in the examples, eg Rounding. On the other hand, I find the Help:Convert messages much more at useful explaining the specific problems involved.

Proposed manual for Convert[edit]

Basic operation - for beginners[edit]

There are four stages to using the {{convert}} template:

  1. Decide on the value for conversion, and the units you want to convert from and to (given in column 2), and start filling in the template (input) with the relevant 'unit-codes' from column 3. These are the 'unnamed parameters', with the last unnamed parameter being the number for rounding/precision (if required).
  2. Decide how you want the results to be presented (output). The default output uses a mixture of full 'unit names' and 'unit-symbols' by adding various 'named parameters' such as |abbr= (also called 'display options', or simply 'options'). Click 'Show preview'.
  3. Convert then calculates the measurements from one unit to the other.
  4. Last, the template dynamically presents the results (output), depending on parameters (or 'display options') such as |abbr=

Example with defaults explained[edit]

NB: This is just ASCII art in a table, my technical ability stops not far from here. The terms like 'unnamed parameter' need changing, but this gives a general at-a-glance outline of what is needed.

        Default input with basic 'input options' only : calculates the conversion
                     1st unnamed parameter: value for conversion
                     |     2nd unnamed parameter: 'unit-code' to convert from
                     |     |     3rd unnamed parameter: 'unit-code' to convert to
                     |     |     |            Default output : presents the results
                     |     |     |                    Left-hand side displays 'unit name' in full
                     |     |     |                    |         Converted value rounded to ?decimal places / ?sig. figures
                     |     |     |                    |         |    Right-hand side displays abbreviated 'unit-symbol'
                                                     
{{convert|1|kg|lb}} → 1 kilogram (2.2 lb)
{{convert|1|lb|kg}} → 1 pound (0.45 kg)

Every unit-code has a default unit to convert to: see column 6. Litres convert by default to → imperial gallons, kilometres → miles, grams → ounces, etc. You can leave out the third unnamed parameter if you only want the default conversion.

                     |     |     3rd unnamed parameter not needed for default conversion!
                           
{{convert|1|kg}} → 1 kilogram (2.2 lb)
{{convert|1|lb}} → 1 pound (0.45 kg)
NB! Column 6 shows the two units as standard written abbreviations, thus: 1.0 kg (2.2 lb).
However, only the unit-codes in column 3 can/must be used as unnamed parameters.

Parameters (or options)[edit]

The {{convert}} template deals with and converts between units of measurement. However, it's best not to think too much about the word 'unit' by itself, since the term is used in three very specific ways within the documentation: 'unit-code', 'unit name', and 'unit-symbol', described below. The term 'parameter' is also frequently used, in terms such as 'unnamed parameter' and 'named parameter' (sometimes called 'option').

At least two 'unnamed parameters' are essential: 'named parameters' are optional, and alter the displayed result.

                    |-unnamed parameters--| |-----------named parameters------------|
                     |----- Input options -----| |------------Output options----------------|
                                                                                       
{{convert|36.21|km|nmi mi|5|abbr=out|sp=us|sigfig=3|lk=on}}
Input options
                     1st unnamed parameter: value to convert
                     |     2nd unnamed parameter: 'unit-code' (column 3) to convert from. For the default unit to convert to, see column 6
                     |     |     3rd unnamed parameter: 'unit-code' (column 3) to convert to. Not needed for default conversion, see column 6
                     |     |     |     4th & 5th unnamed parameters (NB no | separator): unit-code(s) for multiple conversion (see column 7)
                     |     |     |     |     |     last unnamed parameter: value for precision or rounding (whole number)
                     |     |     |     |     |     |
{{convert|1|kg|lb oz ozt|2}}
{{convert|1|kg|lb oz ozt|2}} → 1 kilogram (2.20 lb; 35.27 oz; 32.15 ozt)


Here are the conversions, without and with the named parameters:
{{convert|36.21|km|nmi mi|5}} → 36.21 kilometres (19.55184 nmi; 22.49985 mi)
{{convert|36.21|km|nmi mi|5|abbr=out|sp=us|sigfig=3|lk=on}} → 36.21 kilometers (19.55184 nmi; 22.49985 mi)

Convert normally uses British spelling for the 'unit names' (metre, kilometre). The notes in column 5 show the alternative U.S. spelling (meter, kilometer), which is enabled by using the |sp=us parameter/option.

Nomenclature (incomplete)[edit]

Maybe there is no advantage to this whole idea, it could be unworkable for various reason I have failed to grasp.

You got this far. This section hopes to arrive at a naming scheme. It's far from complete.

Divided into two main sections, unnamed and named parameters, with each parameter/option/etc. fully documented for each.

'Unnamed parameters' (or 'initial arguments' or 'input options' or something)[edit]

  • 'Input-value' (or 'number to be converted') (required). (e.g. {{convert|2.71)
  • 'Input unit-code' (required). The whole template (I think) is structured around the use of unit-codes. These are the basis of the master tables which are processed by a script to make the conversions. The unit-codes are shown in column 3.
    There must be at least one unit-code (the input, or l-h side unit-code).
    • (optional) 'value separators' like +, -, by,
    • 'Output unit-code' (optional). A typical conversion uses two unit-codes (input & output). If more than two output unit-codes are specified, do not use a separator between them.
    • 'Rounding-value'. (optional). This is a whole number which
  • Every unit-code can be expressed in the displayed result (the output) either in words (the 'unit-name') or by an abbreviation ('unit-symbol').

List of Units - ideas[edit]

This should have comprehensive subsections dealing with each column and what it means, and how the info in each column can be used to customise the output. I found that understanding the meaning of each column in the List of units was very helpful for a beginner, and how the unit-codes in each section in the Master doc are the basis (I think) of the whole template.

  • System
  • 'unit-code', listed in column 3.
  • 'unit-name'. The units to convert from and to are listed in column 2 of the following tables.
  • 'unit-symbol'. (column 4) Abbreviations for output instead of full unit names
  • Notes - Different types of alternative unit-codes:
    • micro-things with μ, degrees ° CKF, and Ångstrom.
    • US-specific things, requiring |sp=us
  • Default conversion units for each unit-code
  • Multiple output combos
Input - unnamed params
  • 'unit-code' (column 3)

The {{convert}} template uses unit-codes, which are similar to (but not necessarily exactly the same as) the usual written abbreviation for a given unit. These 'unit-codes' are given in column 3 of the following tables, and are accepted as input by the {{convert}} template as the second and third unnamed parameters.

Output - named params

The units in the displayed result can be shown either in full (the 'unit name' given in column 2) or abbreviated (the 'unit-symbol' given in column 4)

Equivalent current nomenclature[edit]

NB Some duplication here...

Unnamed parameters
  • unit-code for the unit to be converted from    = left-hand side = input parameter = 2nd unnamed parameter
  • unit-code(s) for the unit(s) to be converted to = right-hand side = output parameter(s) = 3rd, 4th etc. unnamed parameter
  • 'unit name' (column 2)
  • 'unit-symbol' (column 4)
  • rounding-value = last named parameter

Input options (Unnamed parameters)[edit]

Conversion value[edit]

The number to be converted. Can be expressed in:

  • Scientific notation
  • Engineering notation
  • Fractions, with //

Input-codes[edit]

And how they relate to the unit names and unit-symbols

Range separators[edit]

Discusses the table and possible improvements

+ and - ("range separators"?)

I may be wrong, but I don't think that the list of Value range separators works in the same way as the Units list (possibly because it's not generated from a machine-readable source like Module:Convert/documentation/conversion data/doc?) I feel it could do with some re-jigging, to have similar/same columns as the Unit tables.

Rounding option (last unnamed parameter or 'rounding value')[edit]

Rounding factor

If the number is:

For non-mathematicians

If the result has unwanted trailing zeroes, eg 12.34500, reduce the "rounding value" by that number of trailing zeroes:

  • {{convert|1.02875|ft|in|5}} → 1.02875 feet (12.34500 in)
  • {{convert|1.02875|ft|in|3}} → 1.02875 feet (12.345 in)

Default: Uses the same precision as the conversion value (param 1). If no rounding value (or last unnamed parameter) is given, {{convert}} uses

  • No value: outputs some random value, vaguely related to the actual number.
  • If the value is a whole number, xxx?
  • If the value has decimal places, then xxx? (The output uses the number of decimal places, including all trailing zeroes if the number of sig figs is greater than the exact number of decimal places with no trailing zeros - or something???)
  • To display a specific number of significant figures, use |sigfig=<number>

The table below is an adaptation of the table at Significant figures#Rounding and decimal places, which I found very useful in trying to understand the difference. It uses a random value of 12.345, which is exactly 12 x 1.02875 inches: thus the trivial use of ft-in in convert.

I used {{convert}} to make the conversions to output the values in the table. But there's a difference (in one cell) between the original table and the ouput result of {{convert}}. Why? Is it a mistake, or does it highlight the differences between the two level of precision that convert uses?

{{Convert}} code for 'decimal places'
after the point
Rounding to
decimal places
 
Precision
Rounding to
significant digits
{{Convert}} code for sigfigs
for entire number
{{convert|1.02875|ft|in|7}} 12.3450000 7 12.34500 {{convert|1.02875|ft|in|sigfig=7}}
{{convert|1.02875|ft|in|6}} 12.345000 6 12.3450 {{convert|1.02875|ft|in|sigfig=6}}
{{convert|1.02875|ft|in|5}} 12.34500 5 12.345 {{convert|1.02875|ft|in|sigfig=5}}
{{convert|1.02875|ft|in|4}} 12.3450 4 12.35 2.34?! {{convert|1.02875|ft|in|sigfig=4}}
{{convert|1.02875|ft|in|3}} 12.345 3 12.3 {{convert|1.02875|ft|in|sigfig=3}}
{{convert|1.02875|ft|in|2}} 12.35 2 12 {{convert|1.02875|ft|in|sigfig=2}}
{{convert|1.02875|ft|in|1}} 12.3 1 10 {{convert|1.02875|ft|in|sigfig=1}}
{{convert|1.02875|ft|in|0}} 12 0 12.3450* {{convert|1.02875|ft|in|sigfig=0}}
{{convert|1.02875|ft|in|-1}} 10 -1 12.3450* {{convert|1.02875|ft|in|sigfig=-1}}
  • Default:
{{convert|1.02875|ft|in}} → 1.02875 feet (12.3450 in)
{{convert|1.02875|ft|in|5}} → 1.02875 feet (12.34500 in)
{{convert|1.02875|ft|in|sigfig=5}} → 1.02875 feet (12.345 in)



Other ideas for incorporating into the manual[edit]

  • Proposed re-arrangement of the Range table to make it look and work just like the Unit tables - I don't think it does at the moment.
  • + - as unnamed parameters
  • ±Arguments/options/values/parameters
  • Confirm exactly how rounding works...
  • Last unnamed parameter = Rounding: "round number" should be "rounding number" or "number to round by" etc.
  • etc.
  • etc.

Sandbox (hidden)[edit]

NB The rest of this page is just rough stuff with DemoTemplate examples.


Convert/list of units[edit]

This has been transcluded (I hope) from Template:Convert/list of units.

The table below lists units supported by {{convert}}. More complete lists are linked for each dimension. For a complete list of all dimensions, see full list of units.

{{Convert}} uses unit-codes, which are similar to, but not necessarily exactly the same as, the usual written abbreviation for a given unit. These unit-codes are displayed in column 3 of the following tables. These are accepted as input by {{convert}} as the second and third unnamed parameters:

  • {{convert|100|kg|lb}} → 100 kilograms (220 lb)
  • {{convert|100|lb|kg}} → 100 pounds (45 kg)

The unit-codes should be treated as case-sensitive:

  • {{convert|100|Mm|mm}} → 100 megametres (1.0×1011 mm)

The output of {{convert}} can display multiple converted units, if further unit-codes are specified after the second unnamed parameter (without the pipe separator). Typical combination output units are listed below in column 7.

  • {{convert|55|nmi|km mi}} → 55 nautical miles (102 km; 63 mi)
  • {{convert|1|oz|ozt g gr}} → 1 ounce (0.91 ozt; 28 g; 440 gr)

Some units have alternative unit-codes. These are shown in brackets in column 3, e.g. °F (F). Either may be entered for Fahrenheit (but not a lower-case f).

Units[edit]

Explanation[edit]

Explanation
system unit unit-
code
symbol or
abbrev.
notes sample default
conversion
combination
output units
the system(s) to which the unit belongs units listed by name unit-code to use in template symbols shown in output other notes about the units sample of the default conversion for the unit output codes for multiple conversions


Area[edit]

Area
(Full list)
system unit unit-
code
symbol or
abbrev.
notes sample default
conversion
combination
output units
SI square kilometre km2 km2 US spelling: square kilometer
1.0 km2 (0.39 sq mi)
  • km2 sqmi
square metre m2 m2 US spelling: square meter
1.0 m2 (11 sq ft)
  • m2 sqft
square centimetre cm2 cm2 US spelling: square centimeter
1.0 cm2 (0.16 sq in)
  • cm2 sqin
square millimetre mm2 mm2 US spelling: square millimeter
1.0 mm2 (0.0016 sq in)
  • mm2 sqin
non-SI metric hectare ha ha 1.0 ha (2.5 acres)
Imperial
&
US customary
square mile sqmi sq mi 1.0 sq mi (2.6 km2)
  • sqmi km2
acre acre (none) 1.0 acre (0.40 ha)
square yard sqyd sq yd 1.0 sq yd (0.84 m2)
square foot sqft
(sqfoot)
sq ft long code "sqfoot" outputs square foot (and never feet) 1.0 sq ft (0.093 m2)
  • sqft m2 (sqfoot m2)
square inch sqin sq in 1.0 sq in (6.5 cm2)
  • sqin cm2
Other square nautical mile sqnmi sq nmi 1.0 sq nmi (3.4 km2; 1.3 sq mi)
dunam dunam (none) For alternative spellings and definitions see the full list 1.0 dunam (0.0010 km2; 0.00039 sq mi)
tsubo tsubo (none) 1.0 tsubo (3.3 m2)


Density[edit]

Density
system unit unit-
code
symbol or
abbrev.
notes sample default
conversion
combination
output units
Metric kilogram per cubic metre kg/m3 kg/m3 1.0 kg/m3 (1.7 lb/cu yd)
  • kg/m3 lb/ft3 (kg/m3 lb/cuft)
  • kg/m3 lb/yd3 (kg/m3 lb/cuyd)
gram per cubic metre g/m3 g/m3 1.0 g/m3 (0.0017 lb/cu yd)
  • g/m3 kg/m3
  • g/m3 lb/ft3 (g/cm3 lb/cuft)
  • g/m3 lb/yd3 (g/cm3 lb/cuyd)
Imperial
&
US customary
pound per cubic foot lb/ft3 lb/cu ft 1.0 lb/cu ft (0.016 g/cm3)
  • lb/ft3 kg/m3 (lb/cu ft g/m3)
  • lb/ft3 g/m3 (lb/cu ft g/m3)
pound per cubic yard lb/yd3 lb/cu yd 1.0 lb/cu yd (0.59 kg/m3)
  • lb/yd3 kg/m3 (lb/cuyd kg/m3)
  • lb/yd3 g/m3 (lb/cuyd g/m3)


Energy[edit]

Energy
(Full list)
system unit unit-
code
symbol or
abbrev.
notes sample default
conversion
combination
output units
SI gigajoule GJ GJ 1.0 GJ (280 kWh)
megajoule MJ MJ 1.0 MJ (0.28 kWh)
kilojoule kJ kJ 1.0 kJ (240 cal)
hectojoule hJ hJ 1.0 hJ (24 cal)
decajoule daJ daJ 1.0 daJ (2.4 cal)
joule J J 1.0 J (0.24 cal)
decijoule dJ dJ 1.0 dJ (0.024 cal)
centijoule cJ cJ 1.0 cJ (0.0024 cal)
millijoule mJ mJ 1.0 mJ (0.00024 cal)
microjoule μJ (uJ) μJ 1.0 μJ (2.4×10−7 cal)
nanojoule nJ nJ 1.0 nJ (2.4×10−10 cal)
cgs megaerg Merg Merg 1.0 Merg (0.10 J)
kiloerg kerg kerg 1.0 kerg (0.10 mJ)
erg erg (none) 1.0 erg (0.10 μJ)
Watt-hour multiples terawatt-hour TWh TWh 1.0 TWh (3.6 PJ)
TW.h TW⋅h
gigawatt-hour GWh GWh 1.0 GWh (3.6 TJ)
GW.h GW⋅h
megawatt-hour MWh MWh 1.0 MWh (3.6 GJ)
MW.h MW⋅h
kilowatt-hour kWh kWh 1.0 kWh (3.6 MJ)
kW.h kW⋅h
watt-hour Wh Wh 1.0 Wh (3.6 kJ)
W.h W⋅h
Electron-
volt
multiples
gigaelectronvolt GeV GeV 1.0 GeV (0.16 nJ)
megaelectronvolt MeV MeV 1.0 MeV (0.16 pJ)
kiloelectronvolt keV keV 1.0 keV (0.16 fJ)
electronvolt eV eV 1.0 eV (0.16 aJ)
millielectronvolt meV meV 1.0 meV (0.16 zJ)
Calorie multiples calorie Cal Cal The thermo-chemical calorie is the default definition. For others, see the full list. 1.0 Cal (4.2 kJ)
megacalorie Mcal Mcal 1.0 Mcal (4.2 MJ)
kilocalorie kcal kcal 1.0 kcal (4.2 kJ)
calorie cal cal 1.0 cal (4.2 J)
millicalorie mcal mcal 1.0 mcal (4.2 mJ)
pound/
ounce
-foot/
inch-hour-minute-second
foot-poundal ftpdl ft⋅pdl 1.0 ft⋅pdl (0.042 J)
foot-pound force ftlbf ft⋅lbf 1.0 ft⋅lbf (1.4 J)
ftlb-f ft⋅lbf
inch-pound force inlbf in⋅lbf 1.0 in⋅lbf (110 mJ)
inlb-f in⋅lbf
inch-ounce force inozf in⋅ozf 1.0 in⋅ozf (7.1 mJ)
inoz-f in⋅ozf
horsepower-hour hph hp⋅h 1.0 hp⋅h (0.75 kWh)
British thermal unit British thermal unit Btu Btu The International Steam Table British thermal unit is used. For others, see the full list. 1.0 Btu (1.1 kJ)
BTU BTU
TNT-based units gigatonne of TNT GtTNT (none) 1.0 gigatonne of TNT (4.2 EJ)
gigaton of TNT GtonTNT (none)
megatonne of TNT MtTNT (none) 1.0 megatonne of TNT (4.2 PJ)
megaton of TNT MtonTNT Mt
kilotonne of TNT ktTNT (none) 1.0 kilotonne of TNT (4.2 TJ)
kiloton of TNT ktonTNT kt
tonne of TNT tTNT (none) 1.0 tonne of TNT (4.2 GJ)
ton of TNT tonTNT (none)
Other
Hartree Eh Eh 1.0 Eh (27 eV)
rydberg Ry Ry 1.0 Ry (14 eV)
tonne of oil equivalent toe toe 1.0 toe (42 GJ)
barrel of oil equivalent BOE BOE 1.0 BOE (6.1 GJ)
cubic foot of natural gas cuftnaturalgas (cufootnaturalgas) Unit-code cufootnaturalgas will show "cubic foot of natural gas" if plural. 1.0 cubic foot of natural gas (1.1 MJ)


Force[edit]

Force
(Full list)
system unit unit-
code
symbol or
abbrev.
notes sample default
conversion
combination
output units
SI giganewton GN GN Allows triple output units. See: full list. 1.0 GN (220,000,000 lbf)
  • GN LT-f
  • GN LTf
  • GN ST-f
  • GN STf
meganewton MN MN Allows triple output units. See: full list. 1.0 MN (220,000 lbf)
  • MN LT-f
  • MN LTf
  • MN ST-f
  • MN STf
kilonewton kN kN Allows triple output units. See: full list. 1.0 kN (220 lbf)
  • kN LT-f
  • kN LTf
  • kN ST-f
  • kN STf
newton N N 1.0 N (0.22 lbf)
  • N lb-f
  • N lbf
  • N oz-f
  • N ozf
millinewton mN mN 1.0 mN (0.0036 ozf)
  • mN oz-f
  • mN ozf
  • mN gr-f
  • mN grf
micronewton μN (uN) μN 1.0 μN (0.0016 grf)
  • μN gr-f
  • μN grf
nanonewton nN nN 1.0 nN (1.6×10−6 grf)
  • nN gr-f
  • nN grf
cgs megadyne Mdyn Mdyn 1.0 Mdyn (2.2 lbf)
kilodyne kdyn kdyn 1.0 kdyn (0.036 ozf)
dyne dyn
(dyne)
dyn 1.0 dyn (0.016 grf)
millidyne mdyn mdyn 1.0 mdyn (1.6×10−5 grf)
Metric gravitational units tonne-force t-f tf 1.0 tf (9.8 kN; 0.98 LTf; 1.1 STf)
tf tf
kilogram-force kg-f kgf 1.0 kgf (9.8 N; 2.2 lbf)
kgf kgf
gram-force g-f gf 1.0 gf (9.8 mN; 0.035 ozf)
gf gf
milligram-force mg-f mgf 1.0 mgf (9.8 μN; 0.015 grf)
mgf mgf
Avoirdupois-based units poundal pdl pdl 1.0 pdl (0.14 N)
long ton-force LT-f LTf 1.0 LTf (10.0 kN)
  • LT-f ST-f
LTf long ton-force
  • LTf STf
short ton-force ST-f STf 1.0 STf (8.9 kN)
  • ST-f LT-f
STf short ton-force
  • STf LTf
pound-force lb-f lbf 1.0 lbf (4.4 N)
lbf lbf
grain-force gr-f grf 1.0 grf (640 μN)
grf grf


Length[edit]

Length
(Full list)
system unit unit-
code
symbol or
abbrev.
notes sample default
conversion
combination
output units
SI megametre Mm Mm US spelling: megameter
1.0 Mm (620 mi)
kilometre km km US spelling: kilometer
1.0 km (0.62 mi)
  • km mi
metre m m US spelling: meter
1.0 m (3 ftin)
  • m ft
  • m ftin
centimetre cm cm US spelling: centimeter
1.0 cm (0.39 in)
  • cm in
millimetre mm mm US spelling: millimeter
1.0 mm (0.039 in)
  • mm in
micrometre μm (um) μm US spelling: micrometer
1.0 μm (3.9×10−5 in)
nanometre nm nm US spelling: nanometer
1.0 nm (3.9×10−8 in)
non-SI metric ångström Å
(angstrom)
Å 1.0 Å (3.9×10−9 in)
Imperial
&
US customary
mile mi mi 1.0 mi (1.6 km)
  • mi km
furlong furlong (none) 1.0 furlong (660 ft; 200 m)
chain chain (none) 1.0 chain (66 ft; 20 m)
rod rd rd For other names of this unit see the full list. 1.0 rd (17 ft; 5.0 m)
fathom fathom (none) fathom ≡ 6 ft 1.0 fathom (6.0 ft; 1.8 m)
yard yd yd assumes the international definition 1.0 yd (0.91 m)
foot ft (foot) ft long code "foot" outputs foot (and never feet)

Use of ′ and ″ symbols violates MOSNUM so is not provided.

1.0 ft (0.30 m)
  • ftin (feet and inches)
  • ft m (foot m)
inch in in Use of ′ and ″ symbols violates MOSNUM so is not provided. 1.0 in (25 mm)
  • in cm
  • in mm
Other nautical mile nmi nmi the international standard nautical mile
For other nautical miles see the full list.
1.0 nmi (1.9 km; 1.2 mi)
parsec pc pc 1.0 pc (3.3 ly)
light-year ly ly 1.0 ly (63,000 AU)
astronomical unit AU AU 1.0 AU (150,000,000 km; 93,000,000 mi)


Mass[edit]

Mass
(Full list)
system unit unit-
code
symbol or
abbrev.
notes sample default
conversion
combination
output units
SI kilogram kg kg Allows triple output units. See: full list. 1.0 kg (2.2 lb)
  • kg lb
  • kg st
gram g g 1.0 g (0.035 oz)
  • g oz
milligram mg mg 1.0 mg (0.015 gr)
  • mg gr
microgram μg (ug) μg 1.0 μg (1.5×10−5 gr)
non-SI metric tonne t t Allows triple output units. See: full list. 1.0 t (0.98 long tons; 1.1 short tons)
  • t LT
  • t ST
metric ton MT t
  • MT LT
  • MT ST
Avoirdupois long ton LT (none) 2,240 lb
used mostly in the British Commonwealth.
Allows triple output units. See: full list.
1.0 long ton (1.0 t)
  • LT t
  • LT MT
  • LT ST
long ton long ton
short ton ST (none) 2,000 lb
used mostly in the US.
Allows triple output units. See: full list.
1.0 short ton (0.91 t)
  • ST t
  • ST MT
  • ST LT
short ton short ton
stone st st 14 lb
used previously in the British Commonwealth except Canada.
Allows triple output units. See: full list.
1.0 st (14 lb; 6.4 kg)
  • st kg
  • st lb
pound lb lb Allows triple output units. See: full list. 1.0 lb (0.45 kg)
  • lb kg
  • lb st
ounce oz oz 1.0 oz (28 g)
  • oz g
drachm drachm (none) 1.0 drachm (1.8 g)
drachm dram (none)
grain gr gr equivalent to the troy grain 1.0 gr (0.065 g)
Troy troy ounce ozt ozt 1.0 ozt (1.1 oz; 31 g)
other carat carat (none) 1.0 carat (0.20 g)


Speed[edit]

Speed
(Full list)
system unit unit-
code
symbol or
abbrev.
notes sample default
conversion
combination
output units
SI metre per second m/s m/s US spelling: meter per second
1.0 m/s (3.3 ft/s)
  • m/s ft/s (m/s foot/s)
non-SI metric kilometre per hour km/h km/h US spelling: kilometer per hour
1.0 km/h (0.62 mph)
  • km/h mph
Imperial
&
US customary
mile per hour mph mph 1.0 mph (1.6 km/h)
  • mph km/h
  • mph kn
foot per second ft/s (foot/s) ft/s long code "foot/s" outputs foot per second (and never feet) 1.0 ft/s (0.30 m/s)
  • ft/s m/s
Maritime units knot kn (knot) kn 1.0 kn (1.9 km/h; 1.2 mph)
  • kn mph


Temperature[edit]

Temperature
(Full list)
system unit unit-
code
symbol notes sample default
conversion
combination
output units
SI K K K Allows triple output units. See: full list. 1.0 K (−272.15 °C; −457.87 °F)
  • K °C (K C)
  • K °R (K R)
  • K °F (K F)
°C °C (C) °C 1.0 °C (33.8 °F)
  • °C K (C K)
  • °C °R (C R)
  • °C °F (C F)
Imperial
&
US customary
°R °R (R) °R 1.0 °R (0.556 K; −458.670 °F; −272.594 °C)
  • °R K (R K)
  • °R °C (R C)
  • °R °F (R F)
°F °F (F) °F 1.0 °F (−17.2 °C)
  • °F K (F K)
  • °F °C (F C)
  • °F °R (F R)
Celsius change C-change Used for temperature intervals instead of actual temperatures
Example:  {{convert|5|C-change|0}} warmer
Result: 5 °C (9 °F) warmer
Fahrenheit change F-change Used for temperature intervals instead of actual temperatures
Example:  {{convert|10|F-change|0}} colder
Result: 10 °F (6 °C) colder


Torque[edit]

Torque
(Full list)
system unit unit-
code
symbol or
abbrev.
notes sample default
conversion
combination
output units
Industrial
SI newton-metre Nm N⋅m Triple combinations are also possible. See the full list. 1.0 N⋅m (0.74 lbf⋅ft)
  • Nm kg.m
  • Nm lb.ft
Non-SI metric kilogram metre kg.m kg⋅m 1.0 kg⋅m (9.8 N⋅m; 7.2 lb⋅ft)
  • kg.m Nm
  • kg.m lb.ft
Imperial
&
US customary
pound force-foot lb.ft lb⋅ft 1.0 lb⋅ft (1.4 N⋅m)
  • lb.ft Nm
  • lb.ft kg-m
Scientific
SI newton-metre N.m N⋅m Triple combinations are also possible. See the full list. 1.0 N⋅m (0.74 lbf⋅ft)
  • N.m kgf.m
  • N.m lbf.ft
Non-SI metric kilogram force-metre kgf.m kgf⋅m 1.0 kgf⋅m (9.8 N⋅m; 7.2 lbf⋅ft)
  • kgf.m N.m
  • kgf.m lbf.ft
Imperial
&
US customary
pound force-foot lbf.ft lbf⋅ft 1.0 lbf⋅ft (1.4 N⋅m)
  • lbf.ft N.m
  • lbf.ft kgf.m


Volume[edit]

Volume
(Full list)
system unit unit-
code
symbol or
abbrev.
notes sample default
conversion
combination
output units
SI cubic metre m3 m3 US spelling: cubic meter
one kilolitre
1.0 m3 (35 cu ft)
cubic centimetre cm3 cm3 US spelling: cubic centimeter
one millilitre
1.0 cm3 (0.061 cu in)
cc cc
cubic millimetre mm3 mm3 US spelling: cubic millimeter
1.0 mm3 (6.1×10−5 cu in)
non-SI metric kilolitre kl kl US spelling: kiloliter
one cubic metre
1.0 kl (35 cu ft)
kL kL
litre l L US spelling: liter
one cubic decimetre
Allows triple output units. See: full list.
1.0 L (0.22 imp gal; 0.26 US gal)
  • l impgal
  • l USgal
  • l U.S.gal
  • l USdrygal
  • l U.S.drygal
L L
  • L impgal
  • L impqt
  • L USgal
  • L U.S.gal
  • L USdrygal
  • L U.S.drygal
centilitre cl cl US spelling: centiliter
1.0 cl (0.35 imp fl oz; 0.34 US fl oz)
cL cL
millilitre ml ml US spelling: milliliter
one cubic centimetre
1.0 ml (0.035 imp fl oz; 0.034 US fl oz)
  • ml impoz
  • ml USoz
  • ml U.S.oz
mL mL
  • mL impoz
  • mL USoz
  • mL U.S.oz
Imperial
&
US customary
cubic yard cuyd cu yd 1.0 cu yd (0.76 m3)
cubic foot cuft (cufoot) cu ft long code "cufoot" outputs cubic foot (and never feet) 1.0 cu ft (0.028 m3)
cubic inch cuin cu in 1.0 cu in (16 cm3)
Imperial imperial barrel impbbl imp bbl 36 imp gal 1.0 imp bbl (160 L; 36 imp gal; 43 US gal)
imperial bushel impbsh imp bsh 8 imp gal 1.0 imp bsh (36 L; 8.0 imp gal; 8.3 US dry gal)
impbu imp bu
imperial gallon impgal imp gal 4.54609 litres by definition, also
4 imp qt or 8 imp pt or 160 imp fl oz
Allows triple output units. See: full list.
1.0 imp gal (4.5 L; 1.2 US gal)
  • impgal l
  • impgal L
  • impgal USgal
  • impgal U.S.gal
  • impgal USdrygal
  • impgal U.S.drygal
imperial quart impqt imp qt 1/4 imp gal or 40 imp fl oz 1.0 imp qt (1,100 ml; 38 US fl oz)
imperial pint imppt imp pt 1/8 imp gal or 20 imp fl oz 1.0 imp pt (0.57 L)
imperial fluid ounce impoz (impfloz) imp fl oz 1/160 imp gal 1.0 imp fl oz (28 ml; 0.96 US fl oz)
  • impoz USoz
  • impoz U.S.oz
  • impoz ml
  • impoz mL
US customary
liquid measure
US barrel USbbl US bbl 31½ US gal
used for liquids except for oil and beer (see the full list)
1.0 US bbl (120 L; 32 US gal; 26 imp gal)
U.S.bbl U.S. bbl
barrel oilbbl bbl 42 US gal 1.0 bbl (0.16 m3)
US beer barrel USbeerbbl
(usbeerbbl)
US bbl 1.0 US bbl (120 L; 31 US gal; 26 imp gal)
U.S.beerbbl
(usbeerbbl)
U.S. bbl
US gallon USgal US gal 231 cubic inches by definition, also
4 US qt or 8 US pt or 128 US fl oz
Allows triple output units. See: full list.
1.0 US gal (3.8 L; 0.83 imp gal)
  • USgal l
  • USgal L
  • USgal impgal
U.S.gal U.S. gal
  • USgal l
  • USgal L
  • USgal impgal
US quart USqt US qt 1/4 US gal or 32 US fl oz 1.0 US qt (950 ml)
U.S.qt U.S. qt
US pint USpt US pt 1/8 US gal or 16 US fl oz 1.0 US pt (0.47 L; 0.83 imp pt)
U.S.pt U.S. pt
US fluid ounce USoz
(USfloz)
US fl oz 1/128 US gal 1.0 US fl oz (30 ml)
  • USoz ml
  • USoz mL
  • USoz impoz
U.S.oz
(U.S.floz)
U.S. fl oz
  • U.S.oz ml
  • U.S.oz mL
  • U.S.oz impoz
US customary
dry measure
US dry barrel USdrybbl US dry bbl 105/32 US bsh 1.0 US dry bbl (0.12 m3)
U.S.drybbl U.S. dry bbl
US bushel USbsh US bsh 2150.42 cubic inches by definition 1.0 US bsh (35 L; 8.0 US dry gal; 7.8 imp gal)
U.S.bsh U.S. bsh
US bushel USbu US bu 2150.42 cubic inches by definition 1.0 US bu (35 L; 8.0 US dry gal; 7.8 imp gal)
U.S.bu U.S. bu
US dry gallon USdrygal US dry gal 1/8 US bsh
Allows triple output units. See: full list.
1.0 US dry gal (4.4 L)
  • USdrygal l
  • USdrygal L
  • USdrygal impgal
U.S.drygal U.S. dry gal
  • U.S.drygal l
  • U.S.drygal L
  • U.S.drygal impgal
US dry quart USdryqt US dry qt 1/32 US bsh 1.0 US dry qt (1,100 ml)
U.S.dryqt U.S. dry qt
US dry pint USdrypt US dry pt 1/32 US bsh 1.0 US dry pt (550 ml)
U.S.drypt U.S. dry pt


Extra[edit]

Pressure
(Full list)
unit unit-
code
symbol or
abbrev.
sample default
conversion
gigapascal GPa GPa 1.0 GPa (150,000 psi)
megapascal MPa MPa 1.0 MPa (150 psi)
kilopascal kPa kPa 1.0 kPa (0.15 psi)
hectopascal hPa hPa 1.0 hPa (0.015 psi)
pascal Pa Pa 1.0 Pa (0.00015 psi)
millipascal mPa mPa 1.0 mPa (1.5×10−7 psi)
millibar mbar mbar 1.0 mbar (1.0 hPa)
mb mb
decibar dbar dbar 1.0 dbar (10 kPa)
bar bar (none) 1.0 bar (100 kPa)
kilobarye kBa kBa 1.0 kBa (1.0 hPa)
barye Ba Ba 1.0 Ba (0.10 Pa)
standard atmosphere atm atm 1.0 atm (100 kPa)
torr Torr Torr 1.0 Torr (0.13 kPa)
millimetre of mercury mmHg mmHg 1.0 mmHg (0.13 kPa)
inch of mercury inHg inHg 1.0 inHg (3.4 kPa)
pound per square inch psi psi 1.0 psi (6.9 kPa)


Fuel efficiency[edit]

Fuel efficiency
unit unit-
code
notes combinations
kilometres per litre km/l (km/L) Use km/L to get "km/L"
  • km/l mpgimp
  • km/l mpgus
litres per 100 kilometres l/100 km (L/100 km) Use L/100 km to get "L/100 km"
  • l/100 km mpgimp
  • l/100 km mpgus
litres per kilometre l/km (L/km) Use L/km to get "L/km"
  • l/km impgal/mi
  • l/km usgal/mi
miles per imperial gallon mpgimp
  • mpgimp mpgus
miles per US gallon mpgus (mpgUS, mpgU.S.) Use mpgUS to get "US"

Use mpgU.S. to get "U.S."
mpgus will give "U.S." if spelling is
set to US & "US" otherwise

  • mpgus mpgimp
imperial gallons per mile impgal/mi
  • impgal/mi
US gallons per mile usgal/mi (USgal/mi, U.S.gal/mi) As above with the us vs US vs U.S.
  • usgal/mi
The mpgUS, mpgU.S., USgal/mi vs U.S.gal/mi, km/L, L/100 km and L/km variants work within combinations also (making 36 combinations in total).


Population density[edit]

Population density
unit unit-
code
notes combinations
inhabitants per square kilometre PD/km2 PD stands for population density, i.e. humans (inhabitants)
  • PD/km2 PD/sqmi
per square kilometre /km2 Used when the word 'inhabitants' would be inappropriate.
  • /km2 /sqmi
inhabitants per hectare PD/ha
  • PD/ha PD/acre
per hectare /ha
  • /ha /acre
inhabitants per square mile PD/sqmi PD stands for population density, i.e. humans (inhabitants)
  • PD/sqmi PD/km2
per square mile /sqmi Used when the word 'inhabitants' would be inappropriate.
  • /sqmi /km2
inhabitants per acre PD/acre
  • PD/acre PD/ha
per acre /acre
  • /acre /ha


Cost per unit mass[edit]

Cost per unit mass
unit unit-
code
notes combinations
dollars per pound $/lb "$" can mean US$, HK$, etc.
  • (none)
dollars per kilogram $/kg
  • (none)
dollars per troy ounce $/ozt 12 troy ounces in 1 troy pound
  • (none)


The hat letter[edit]

The hat letter, or Why some ideas fail to make it into the out tray. I remember reading something like this a very long time ago, in a book by someone like James Thurber or Stephen Leacock or Leo Rosten. Re-constructed from memory, with a few extra invented phrases. Anyone recognise it, or something like?

Messrs. Sue, Grabbitt & Runne,
127 Lincoln's Inn,
London WC2
Date as postmark
Dear Sirs,
re: Final Demand for Payment, your ref. 192/1828/4B-673
Thank you for your letter of the 2nd inst.
You are evidently unaware of the method we use for paying our bills.
At the end of every month we receive a statement from our bank, telling us how much money we have. We then write the names of each of our creditors and the amount due them on a slip of paper, and place all the slips in a hat. Next - averting our gaze in order to encourage an expectant sense of the random - we pull one slip at a time out of the hat, write out a cheque for the full amount to the creditor, seal it in a stamped addressed envelope and put in the letter tray. We continue to repeat this simple exercise until there is no more money left. At the end of the following month, we write the names of our remaining creditors on slips of paper … and so it goes.
We therefore beg to inform you that if you persist in sending us any further letters, your name will not even go in the damn hat.
Faithfully yours,


pp Acme Manual Co., Inc.