Template talk:Convert

Frequently asked questions

Q: When using {{convert}} why does the answer sometimes seem a bit off?

A: This template takes into account the precision of the supplied value and generally rounds the output to the same level of precision. If you need to change from the default output precision, see rounding.

Note: This can cause whole numbers that end in one or more zeroes to be converted less accurately than expected.

Q: What are all the possible units (kg, lb, m, cm, ft, in, °C, °F, km, mi, nmi, mph, km/h, and so on)?

A: See Help:Convert units for an introduction and Module:Convert/documentation/conversion data for the complete list.

Q: I've been using Convert for some time and am pretty comfortable with its basic features. Does it have other features which it would be worth my while to learn about?

A: Almost certainly. Start with Help:Convert.

For more, see the FAQ.

Template:Convert is permanently protected from editing because it is a heavily used or highly visible template. Substantial changes should first be proposed and discussed here on this page. If the proposal is uncontroversial or has been discussed and is supported by consensus, editors may use {{edit template-protected}} to notify an administrator or template editor to make the requested edit. Usually, any contributor may edit the template's documentation to add usage notes or categories.

Any contributor may edit the template's sandbox. Functionality of the template can be checked using test cases.

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Template:Convert

... in conception

... and in reality

A new double conversion

For Reciprocating engine#History {{convert|2,300|metric ton|short ton long ton|lk=on}} and {{convert|2,300|metric ton|ST LT|lk=on}} 2,300 metric tons (^{[convert: unknown unit]}) and 2,300 metric tons (2,535 short tons; 2,264 long tons) instead of {{convert|2,300|metric ton|short ton|lk=on}} or {{convert|2,300|metric ton|long ton|lk=on|sigfig=4}} 2,300 metric tons (2,535 short tons) or 2,300 metric tons (2,264 long tons) Peter Horn User talk 01:54, 6 October 2024 (UTC)[reply]

@Peter Horn: When a unit code such as short ton contains a space, use + to separate units:

{{convert|2,300|metric ton|short ton+long ton|lk=on}} → 2,300 metric tons (2,500 short tons; 2,300 long tons)

Johnuniq (talk) 02:09, 6 October 2024 (UTC) Peter Horn User talk 02:41, 6 October 2024 (UTC)[reply]

Thanks. Peter Horn User talk 02:49, 6 October 2024 (UTC)[reply]

Possible bug report re: temperature units

Input:

{{Convert|1|K|C F|abbr=~}}
{{Convert|1|C|F|abbr=~}}
{{Convert|1|C|F|abbr=off}}
{{Convert|1|K|C F|abbr=off}}
{{Convert|1|Celsius|F|abbr=~}}
{{Convert|1|Fahrenheit|Celsius}}
{{Convert|1|C|kelvin|abbr=~}}

Output:
1 K [K] (−272.15 °C; −457.87 °F)
1 °C [°C] (34 °F)
1 degree Celsius (34 degrees Fahrenheit)
1 kelvin (−272.15 degrees Celsius; −457.87 degrees Fahrenheit)
1 °C [°C] (34 °F)
1 Fahrenheit^{[convert: unknown unit]}
1 °C [°C] (^{[convert: unknown unit]})

Semi-expected output:
1: 1 kelvin [K]
2: 1 degree Celsius [°C]
3 & 4: N/A, working
5: 1 degree Celsius [°C]

And last 2, certainly slightly surprising behavior that it outputs the unit names but doesn't recognize some as input. But it does for Celsius. If that's known/intended behavior, ought to be documented somewhere. (There, then it's not a bug, b/c you documented it—now it's a feature )

Contrasted:
1 inch [in] (0.083 ft; 2.5 cm)
1 inch (2.5 cm)
1 kilometre (5.0 furlongs)
Slowking Man (talk) 23:14, 7 October 2024 (UTC)[reply]

Convert has a lot of quirks due to its long history. The proper documentation is at Module:Convert/documentation/conversion data#Temperature. Various summaries of the units are available but I don't like the advice they give for temperature because they suggest that {{convert|30|°C}} is the approved method whereas it should actually be {{convert|30|C}} on the basis that unit codes are intended to be easy to type and it is not necessary to remember that it is K (kelvin) but °C (degrees Celsius). At any rate, for obscure historical reasons, Celsius was defined as an alias for C but the other names were not defined. If anything, I would recommend removing Celsius. Johnuniq (talk) 01:05, 8 October 2024 (UTC)[reply]

I started wondering if the OP was more concerned about the fact that abbr=~ produces °C [°C]. That option is rarely used. Most units default to showing the name for the input (for example, 30 kilograms). Using abbr=~ would display 30 kilograms [kg]). That is, it shows the symbol as well as the name. It turns out that temperature units default to showing the symbol and you have to use abbr=off to make them show the name. That means you cannot also use abbr=~ so it is not possible to show the name and symbol for a temperature unit. That is not ideal but probably is not worth fixing. See Template talk:Convert/Archive December 2014#What happened with abbr=~ ? for a discussion of whether the option should be deprecated. Johnuniq (talk) 02:08, 8 October 2024 (UTC)[reply]

WMF needs to determine your IRL identity and insure your life for $10,000,000 -- the conservative cost of hiring a staff of coders to take over maintenance of convert, should the worst happen. E Eng 03:24, 8 October 2024 (UTC)[reply]

I would take you up on that great idea if it were not for my nervousness regarding giving someone a $10,000,000 reason for me to disappear! Johnuniq (talk) 03:55, 8 October 2024 (UTC)[reply]

With the right paperwork, a "reported" death and a new life in Cuba, you could have a rather nice retirement plan :)

On an unrelated note, I'd completely forgotten that I had commented on this 10 years ago. But having never used it even once, I'm in favour of removing it. Is it used much?

Sounds like the OP's gripe is that Fahrenheit and kelvin are valid outputs but not valid inputs. Considering we also have meters, miles, feet, inches, etc as inputs, I tend to agree with him. Stepho talk 07:08, 8 October 2024 (UTC)[reply]

Gotta watch out for that template mafia. Extremely groan-worthy memeing attempt:

{{that's|how={{{mafia|{{{works}}}}}}}}

(for those not getting it) --Slowking Man (talk) 23:14, 8 October 2024 (UTC)[reply]

Hah, not surprising (I've seen scarier corner cases in old code for sure). Wanted to be helpful mainly and ensure this was known. Certainly understand if people aren't rushing in to overhaul the template code. Would be good to document the behavior somewhere I think. Where do people think is the best place to put that? Wouldn't mind writing up a note in the docs. Thanks for the expert knowledge!

--Slowking Man (talk) 23:14, 8 October 2024 (UTC)[reply]

Ranges of ranges of values

In technical plant descriptions (e.g. floras), dimensions of plant parts are often given in ranges of ranges: "5-15 x 4-8 mm". Is there a way to get {{convert}} to handle that appropriately, i.e. "5-15 x 4-8 mm (0.2-0.6 x 0.2-0.3 in)"? At the moment, {{convert|5|–|15|×|4|-|8|mm|1|abbr=on}} gives "5 mm–15 mm × 4 mm–8 mm (0.2 in–0.6 in × 0.2 in–0.3 in)", which is far too repetitive for readability.

{{convert|5|–|15|mm|1|abbr=on}} x {{convert|4|–|8|mm|1|abbr=on}} is a little better, giving "5–15 mm (0.2–0.6 in) x 4–8 mm (0.2–0.3 in)", but that's still needlessly repetitive. {{convert|5|–|4|mm|1|abbr=on}} x {{convert|15|–|8|mm|1|abbr=on}} gives "5–4 mm (0.2–0.2 in) x 15–8 mm (0.6–0.3 in)", which is also still repetitive, and also incorrectly formatted.

Any advice?

-- Photosynthetic430 ❧ 15:37, 11 October 2024 (UTC)[reply]

According to the documentation, |x| and |abbr=on| combine to output the unit symbol multiple times, as per MOS:UNITSYMBOLS. Replace |x| with |xx| so that {{convert|5|–|15|xx|4|-|8|mm|1|abbr=on}} outputs 5–15 × 4–8 mm (0.2–0.6 × 0.2–0.3 in). Downside is that xx is deprecated and you will be violating MOS:UNITSYMBOLS. Perhaps you should raise the question of whether this format should be used at Wikipedia talk:Manual of Style/Dates and numbers. Stepho talk 15:54, 11 October 2024 (UTC)[reply]

There must be some way in which{{convert|5|–|15|×|4|-|8|mm|1|abbr=values|disp=preunit|mm|in}} giving "5–15 × 4–8 mm (0.2–0.6 × 0.2–0.3 in)" is risky but I haven't figured that out yet. NebY (talk) 16:00, 11 October 2024 (UTC) Ah - anyone using it for anything but mm would have to take care to change both "mm" - otherwise e.g. changing only the first mm to m as {{convert|5|–|15|×|4|-|8|m|1|abbr=values|disp=preunit|mm|in}} gives "5–15 × 4–8 mm (16.4–49.2 × 13.1–26.2 in)". NebY (talk) 16:09, 11 October 2024 (UTC)[reply]

Discussions here about MOS:UNITNAMES resulted in the situation shown above where unit symbols are duplicated. There was a fair bit of pressure to remove a workaround which I retained on the principle that a template should not prevent an editor from exercising judgment. The trick is to use xx instead of x.

{{convert|5|-|15|x|4|-|8|mm|1|abbr=on}} → 5 mm–15 mm × 4 mm–8 mm (0.2 in–0.6 in × 0.2 in–0.3 in)
{{convert|5|-|15|xx|4|-|8|mm|1|abbr=on}} → 5–15 × 4–8 mm (0.2–0.6 × 0.2–0.3 in)

Note that it is better to use a letter x and a hyphen - in the input because they are easier to type and easier for others to copy. Johnuniq (talk) 22:47, 11 October 2024 (UTC)[reply]

Thank you! That's exactly what I needed. -- Photosynthetic430 ❧ 08:12, 13 October 2024 (UTC)[reply]

Pint, half pint, one-third [of an] imperial pint

In Beer festival, are instances of pints related to the United Kingdom units of measurement (imperial pints) or just a type of beer glass?-- Carnby (talk) 17:05, 19 October 2024 (UTC)[reply]

@Carnby: Why are you asking here, and not at Talk:Beer festival? This is the talk page for discussing improvements to Template:Convert. --Redrose64 🌹 (talk) 21:13, 19 October 2024 (UTC)[reply]

@Redrose64: My apologies, just a mistake. But there are some problems involving {{convert}} as well:

there is an instance of the measuring unit "half pint" that I need to convert into litres and US pints;
using {{convert|1/3|imppt|L USpt|1|spell=in|disp=sqbr}} yields one-third imperial pint instead one-third of an imperial pint;
there is an instance of "tubs of cider and perry"; a tub should be about four gallons, according to the Merriam-Webster.

--Carnby (talk) 19:38, 20 October 2024 (UTC)[reply]

Tub (unit) lists different weights for butter/cheese (84 lb), tea (60 lb), camphire (56-86 lb), vermillion (336-448 lb), camphor (130 Dutch lb), coal (100 lb), salt (18 imperial gallons). Stepho talk 20:50, 20 October 2024 (UTC)[reply]

But for cider and perry?-- Carnby (talk) 21:06, 20 October 2024 (UTC)[reply]

You don't have to use Convert. If it doesn't produce the English phrasing you want, you can obtain and insert the value into your phrasing in any way you want. If you'd rather use Convert than a calculator, perhaps to give other editors confidence, you can use it to give only the output value(s) and unit(s) (or even only a value), e.g. one-third of an imperial pint ({{convert|1/3|imppt|L USpt|1|disp=out}}) -> one-third of an imperial pint (0.2 L; 0.4 US pt). More such options are available at Template:Convert/doc#Displaying parts of the result: 2 (1.5). NebY (talk) 21:29, 20 October 2024 (UTC)[reply]

Plans for new version

I am slowly planning a new version of the module. This is mainly a result of a discussion at the Ukrainian Wikipedia regarding a bug in the way variable names are handled. Languages such as Ukrainian have more than one plural form for a unit name. Some examples are at uk:User:Johnuniq/convert with discussion at its talk.

I also want to clean up some minor issues:

Units mile and miles will set abbr=off for that unit. That means {{convert|4|km|miles}} would display "4 kilometres (2.5 miles)" rather than the current "4 kilometres (2.5 mi)". This was mentioned in June 2021.
Think about whether any other aliases should similarly set abbr=off. I would probably leave that for another time as it is only mile/miles that I have noticed being a problem with a result of "mi" when the editor went to the trouble of typing "miles".
Want a fix for {{convert|10|e6kg|e6lb|abbr=unit}} so result can be "10 million kg (22 million pounds)" rather than the current "10 million kg (22 million lb)".
Perhaps add an alias for abbr=~ (maybe adj=~?) to avoid the problem mentioned above. That would allow {{convert|1|C|K|abbr=off|adj=~}} to display "1 degree Celsius [°C] (274 kelvins)".

The abbr=unit issue has been raised several times. The problem is that abbr=off results in "million kilograms" while abbr=on gives the unappealing "10×10^⁶ kg". Using abbr=unit means the units will be abbreviated (kg and lb) while million will not.

I haven't been able to think of a clean way to specify that million should be spelled but I am currently wondering whether this trick would be ok:

e6lb would work as it does now (million or engineering notation depending on abbr).
E6lb would give million (never engineering notation).

Thoughts? Any clean alternative syntax? Johnuniq (talk) 23:34, 21 October 2024 (UTC)[reply]

Here's a couple ideas on expanding abbr options:

Concatenate the options with a delimiter: {{convert|10|e6kg|e6lb|abbr=innum;inunit;outnum;outunit}} would be equivalent to abbr=on. Using a subset of the options would allow fine-tuning the output.
Add parameters abbrin, abbrout, which allow on, off, unit, num.

Indefatigable (talk) 21:21, 25 October 2024 (UTC)[reply]

Thanks, they are good ideas. However, I think I'll go with the simple although obscure E6lb. That is a small extra thing for editors to recall as compared with four new keywords. No matter how convert handles it, people will have difficulty knowing what to do and will have to ask or study the long documentation. An implementation difficulty is that I want to continue supporting other languages and the current translation system would need very large changes to accommodate delimited options. Johnuniq (talk) 01:24, 26 October 2024 (UTC)[reply]

Module version 30

Some changes to the convert modules are in the sandbox and I intend switching the main modules to use the sandbox soon.

Module:Convert • Module:Convert/sandbox • same content
Module:Convert/data • Module:Convert/data/sandbox • same content
Module:Convert/text • Module:Convert/text/sandbox • same content
Module:Convert/extra • Module:Convert/extra/sandbox • same content
Module:Convert/wikidata • Module:Convert/wikidata/sandbox • same content
Module:Convert/wikidata/data • Module:Convert/wikidata/data/sandbox • same content
Option adj=~ is an alias for abbr=~ so either may be used to display the input name and symbol.
- {{convert|1|C|K|abbr=off|adj=~}} → 1 degree Celsius [°C] (274 kelvins)
Option link=... is an alias for lk=... so either may be used to control whether units are linked.
- {{convert|12.3|kn|link=in}} → 12.3 knots (22.8 km/h; 14.2 mph)
Units can be entered with an engineering factor using "e" or "E", for example, e3km or E3km. Using uppercase E3km displays the factor as a word ("thousand") rather than as ×10³. Using lowercase e3km continues to display the word if abbr=unit is used, or if abbr=off applies to the unit.
- {{convert|10|e3mi|e3km}} → 10 thousand miles (16×10^³ km)
- {{convert|10|e3mi|E3km}} → 10 thousand miles (16 thousand km)
- {{convert|10|E6kg|E6lb|abbr=in}} → 10 million kg (22 million pounds)
For ukwiki (and others), function variable_name has been enhanced to use mw.language.getContentLanguage():convertPlural rather than the inadequate home-grown code that was developed for slwiki in 2014. In addition a bug fix to prevent duplication of the local language's equivalent of "kilo" was implemented. See uk:User:Johnuniq/convert and its talk.
For ukwiki, a unit can have a pername that will be used if the unit is the second in a "per". For example, the definition for mi can include the names that it normally has, as well as a pername that would be used in a per unit such as $/mi.
For ukwiki, the eng_scales table in Module:Convert/text has been enhanced to allow variable names for factors such as "kilo" that depend on the value.
Units mile and miles set abbr=off.
- {{convert|4|km|mi}} → 4 kilometres (2.5 mi)
- {{convert|4|km|miles}} → 4 kilometres (2.5 miles)
Module:Convert/makeunits
- The definition for an alias accepts abbr=off to force use of the unit name, not symbol.
- Unit definitions can include a pername.

The above examples use fixed wikitext so the outputs won't change in the future.

For posterity, I will record that Module:Convert/extra has had unit bit since August 2022. It also had byte but I removed it as it was unused and had a small error, and was not supported in October 2020 or in April 2023. Unit bit has a good use in Patterned media so I intend to keep it. Normally, I would move extra units to the main data module but there would have to be another unit (byte) to be the default output for bit. Therefore, I'm just leaving bit as an extra unit for consideration another time.

There is a little more information at #Plans for new version above. Johnuniq (talk) 05:35, 23 October 2024 (UTC)[reply]

Excellent. I'm looking forward to the miles treatment. Stepho talk 23:52, 25 October 2024 (UTC)[reply]

This version is now live. @Slowking Man: {convert|1|C|K|abbr=off|adj=~}} now works (example above). Johnuniq (talk) 23:18, 26 October 2024 (UTC)[reply]

I suppose it's a coincidence that the power just went out in a 10-mile radius around me? E Eng 00:39, 27 October 2024 (UTC)[reply]

👍 Best feature - ever! Stepho talk 00:51, 27 October 2024 (UTC)[reply]

Hey EEng, I'm disappointed. You mean a 10-mile (16 km) radius. Anyway, I'm glad you noticed. Johnuniq (talk) 02:42, 27 October 2024 (UTC)[reply]

A 10-mile radius centred exactly on you? Spoookyy... --Redrose64 🌹 (talk) 08:19, 27 October 2024 (UTC)[reply]

Multiple values, shorter abbreviation?

Is it possible to display a shorter version than

{{convert|149.6x71.5x8.25|2|mm|2}}

149.6 by 71.5 by 8.25 millimetres (5.89 in × 2.81 in × 0.32 in)

Or?

{{convert|149.6x71.5x8.25|mm|2|abbr=on}}

149.6 mm × 71.5 mm × 8.25 mm (5.89 in × 2.81 in × 0.32 in)

In some infoboxes (eg, {{Infobox mobile phone}}), where space is limited, it is desired to list the dimensions of some object, and its conversion, but it seems unnecessary to list the “mm” and the “in” three times. I might be missing something, but I would like an option to display something like:

149.6 × 71.5 × 8.25 mm (5.89 × 2.82 × 0.32 in)

— HTGS (talk) 23:14, 6 November 2024 (UTC)[reply]

Use xx instead of x.

{{convert|149.6xx71.5xx8.25|mm|2}} gives 149.6 × 71.5 × 8.25 mm (5.89 × 2.81 × 0.32 in)

Beware that this technically violates MOS:UNITSYMBOLS. |by| is an option that obeys the MOS (but looks clumsier).

{{convert|149.6|by|71.5|by|8.25|mm|2}} gives 149.6 by 71.5 by 8.25 mm (5.89 by 2.81 by 0.32 in) Stepho talk 23:49, 6 November 2024 (UTC)[reply]

Thank you! I might actually ask at MOSNUM, because this feels like an oversight (for use in small spaces), and I’d like to standardise this across a lot of infoboxes. — HTGS (talk) 00:06, 7 November 2024 (UTC)[reply]

Troy weight

I'm not sure if this is the right place to discuss this, but is it possible to integrate troy weight into this template? Basically another obscure, antiquated unit of mass that still sticks around out of tradition in the precious metals industry. TheTechnician27 (Talk page) 12:23, 10 November 2024 (UTC)[reply]

@TheTechnician27: It's already provided, e.g. {{convert|1|ozt|g|3}} → 1 troy ounce (31.103 g). See full list of mass units. --Redrose64 🌹 (talk) 15:48, 10 November 2024 (UTC)[reply]

@Redrose64: Oooh, thank you! I was trying to use 'oz t' with no success. TheTechnician27 (Talk page) 17:26, 10 November 2024 (UTC)[reply]

Indian numbering system: lakhs and crores

Moved from Module talk:Convert. Johnuniq (talk) 01:45, 19 November 2024 (UTC)[reply]

I request that we enhance the module to include lakhs and crores.

The Indian numbering system is the main nomenclature used in South Asia to name large numbers. From the lead:

The terms lakh or 1,00,000 (one hundred thousand, written as 100,000 in Pakistan, and outside the Indian subcontinent) and crore or 1,00,00,000 (ten million, written as 10,000,000 outside the subcontinent) are the most commonly used terms in Indian English to express large numbers in the system.

This is a dimensionless unit, or if you wish, the units are integers. (Hence if implemented, the data item in 'all_units' at Module:Convert/data could be named ["ins"] for 'Indian numbering system'). Note also the main pattern of comma-separation into groups of two and three digits, not just three.

These terms should be converted to standard English terms, mostly with the term million, except for values up to 9 lakh, which could be 900,000. Sample usage in articles:

lakh – 6,914 articles
crore – 10,809 articles

The plural sometimes has the -s, and sometimes doesn't; so both '2 lakhs' and '2 lahk' are seen; same for crore(s).

This arose at the Rfc at Wikipedia talk:Manual of Style/Dates and numbers, where in my !vote (diff) I called for using template {{Convert}}, only to realize after the fact that the template will not handle it. This conversion is badly needed, as it will resolve a sore point about usage of lakhs and crores in many articles. Thanks, Mathglot (talk) 23:46, 18 November 2024 (UTC)[reply]

Earlier discussions.

I have not yet examined the RfC at WT:Manual of Style/Dates and numbers#RfC Indian numbering conventions. The above discussions point out that lakh and crore are not units. They are like million which is also not a unit. However, if convert could do something useful that is not provided by {{lakh}} and {{crore}}, it could be investigated. Johnuniq (talk) 02:03, 19 November 2024 (UTC)[reply]

The {{lakh}} and {{crore}} templates make more sense than overloading {{convert}}. Stepho talk 23:07, 19 November 2024 (UTC)[reply]