Wikivoyage:Measurements

We often use measurements in Wikivoyage—for the distances between places, for the altitude of mountains, for the temperature of deserts, for the volume of a glass of beer. This style guideline gives some suggestions for how to specify and format measurements, their units and unit abbreviations.

Note: The abbreviations below are bolded for clarity of exposition, but abbreviations in Wikivoyage articles shouldn't be bolded just because they're abbreviations!

Use local units of measurement
When showing a measurement, use the local system of units for the destination you're describing. This is the system that travelers will see on road signs, local maps, menus, food packages, weather reports, etc.

For almost all of the world, this is the metric system. For the United States of America, it's the U.S. system of units—similar to, but certainly not the same as, the imperial system of the United Kingdom. In some cases, the systems are mixed—for example, in the United Kingdom, road distances are measured in miles and beer served by the pint, while meat and canned goods, for example, are measured in (kilo)grams, and milk is measured in either pints and litres. Wikivoyage needs both accuracy and consistency.

The chief difference between the U.S. system of units and the imperial system is in the sizes of the pint and the gallon. The U.S. measures are often 16% smaller than the Imperial measures. That means you get more drunk on a British pint, and you get fewer miles to the gallon on American roads!

For articles that don't deal with a particular destination (like travel topics), use metric along with U.S. or imperial measures when needed or originally specified (e.g., "No more than 3 oz of liquids or gels may be taken through airport security in the U.S.").

Provide conversions
It's easier for travelers to understand measurements if they're converted to their own system—so try to provide conversions for measurements into both the metric (SI) and U.S. styles.

If the preferred units are metric, try to provide U.S. Standard measurements in parentheses. If the preferred units are U.S. Standard, try to provide metric measurements in parentheses. If for some reason the local unit is neither metric nor US, try to provide first metric, then U.S. (separated by a comma) enclosed in the same parentheses afterwards.

Don't repeat conversions unnecessarily and if you provide a conversion, use only the same number of significant digits as the original measure (these measurements are going to be used by travelers, not scientists).

Possibly the easiest way to provide conversions is to do it automatically using a template, either the compact templates below for specific measurements, such as km or mi, or the more general convert template. E.g. or 2 mi produces 2 mi (and 3.2 km makes 3.2 km). To reduce significant digits you can use the sigfig parameter: 5 km gives 5 km.

Sometimes it may be better to use a different unit rather than relying on automatic conversion; for example, Pudong mentions "four buildings over 400 m, a quarter mile high" which may be clearer than "400 m (1320 ft)".

Some numbers do not have convertible units but may be made clearer by a comparison; for example the Fujian article gives the population as "37 million, which is small for a Chinese province (17th of 23) but about the same as Canada, Poland or California."

Avoid orphaned units
Except for measurements of temperature and voltage, we have a mild preference for separating the number from its associated unit by a single space, but:


 * Don't go wild copy editing different formatting
 * To avoid the unit of measurement that "belongs" to a measurement being "orphaned" from its associated unit when it wraps to a following line, separate the pair with a non breaking space character " " rather than a simple space, eg: " " will display 4500 km. You can also use the template nowrap to achieve the same, e.g.:  (include any appended punctuation, to prevent a line break in-between).

Periods and commas
Since this is the English-language version of Wikivoyage, a full stop or period should be used separating any decimal fraction of a number and not a comma, whatever the local practice is, i.e. 10.75, not 10,75.

For similar reasons, never use a full stop or period as the delimiter to separate groups of three numerals left of the decimal point. Use a comma for this purpose instead, i.e. 10,000, not 10.000.

Fractions
It's okay to use fractions for expressing numbers, e.g. for hours or for measurements in the Imperial/U.S. system, but fractions should not be used for measurements in the metric system. Because fractions can be more difficult to read, it is best to stick with the most common, i.e., ½, ¼, and ¾, and use decimals for other numbers, e.g.,
 * 1½ hours, 2¼ miles,
 * But: 1 hr 20 min, 3.5 km, 1 ft 8 in (instead of 1⅓ hr, 3½ km, 1⅔ feet or 1' 8")

Examples
The following are examples of good practice.


 * It's 2,800 mi (4,500 km) from Los Angeles to New York City.
 * It's 815 km (506 mi) from Paris to Marseille.
 * Pikes Peak is 14,110 ft (4,301 m) high.
 * Mount Fuji is 3,776 m (12,388 ft) high.
 * Temperatures in Death Valley routinely hit 110°F (43°C).
 * In winter, Iqaluit gets down to -50°C (-58°F).
 * 5 km (3 mi) to the north is a national park. 5 km to the south is a lake.

However, consider if you can make the prose just as clear to a traveller while avoiding unit conversions.


 * Winter temperatures at night in Canberra can drop below freezing, but snow is rare.
 * The walk to the lake will take around 30 minutes and involves climbing around 30 stairs.

Area
Always abbreviate units in listings. Do not put periods (full stops) after units. Never use an "s" after a unit abbreviation to make it plural. Don't capitalize the first letter of any of the base units below.


 * square meter = m²
 * square kilometer = km²
 * hectare = ha


 * square foot = ft²
 * square yard = yd²
 * square mile = mi²
 * acre = acre

Examples

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Duration
Always abbreviate units in listings – outside the "content" tab that is. Do not put periods (full stops) after units. Never use an "s" after a unit abbreviation to make it plural. Never capitalize the first letter.


 * year = yr (rarely used in abbreviated form)
 * week = wk (rarely used in abbreviated form)
 * hour = hr
 * minute = min
 * second = s or sec

Electrical

 * alternating current = AC
 * direct current = DC
 * ampere(s) or amp(s) = A
 * volt(s) = V
 * cycles per second = Hz

Length
Always abbreviate metric units in listings. Do not put periods (full stops) after units. Never use an "s" after a unit abbreviation to make it plural. Don't capitalize the first letter of any of the base units below.


 * kilometer = km
 * meter = m
 * centimeter = cm
 * millimeter = mm


 * mile = mi
 * yard = yd
 * foot = ft
 * inch = in

Do not use quotation marks (' or ") to signify feet or inches; that would confuse some readers.

Spell nautical miles in full, because some abbreviations, including "nm", conflict with abbreviations for other units (eg. nanometres in the metric system).

Examples

 * "the trail is long" and "it's an  trail"
 * "the trail is long" and "it's an  trail"
 * or  or   – will show as :
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Speed
Show as km/h or mph, not kmh-1, kmph or mi/h.

Examples

 * or  – will show as :
 * or  – will show as :
 * The latest Boeing 787 Dreamliner has a cruising speed of Mach 0.85 (913 km/h, 567 mph) at 10,700 m (35,000 ft)

Temperature
Always abbreviate units in listings.


 * Celsius = degrees Celsius or °C (Don't use the name "centigrade" which was officially deprecated in 1948.)


 * Fahrenheit = degrees Fahrenheit or °F

When referring to places inside the United States, show temperatures in Fahrenheit first followed by Celsius in parentheses. Anywhere else, use Celsius first with Fahrenheit in parentheses.

If the prolix prose form is not chosen, temperature ranges should be shown in this form: &minus;3 °C to 26 °C (rather than "-3°C - 26°C" or "-3°- 26°C")

Once you choose a temperature format, use that format throughout the article. Do not switch back and forth.

Examples

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 * or  – will show as:

Volume
Always abbreviate units in listings. Do not put periods (full stops) after units. Never use an "s" after a unit abbreviation to make it plural. Don't capitalize the first letter of any of the base unit abbreviations below (except for the liter = L).

Dry volume

 * cubic meter = m³
 * cubic centimeter = cm³, or equivalently mL

If you cannot get the ³ on your keyboard, then use 3 which produces a 3.
 * cubic foot = ft³ or cu ft
 * cubic yard = yd³ or cu yd

Fluid volume

 * liter = L
 * milliliter = mL
 * hectoliter = hL

(In order to avoid confusion with the numeral 1 and letter l, L is always capitalized when used as an abbreviation for liter.)


 * pint = pt
 * quart = qt
 * gallon = gal

Weight/mass
Always abbreviate units in listings. Do not put periods (full stops) after units. Never use an "s" after a unit abbreviation to make it plural. Don't capitalize the first letter of any of the base units below.


 * metric ton (US) or tonne (UK) (1000 kg) = t (not Mg)
 * kilogram = kg
 * gram = g
 * milligram = mg


 * hundredweight [100 lb (U.S.) / 112 lb (U.K.)] = cwt
 * short ton (U.S., 2000 lb) / long ton (U.K., 2240 lb) = ton
 * pound = lb
 * ounce = oz

Examples

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