User:W. Frank/Units

We often have to use measurements in Wikivoyage &mdash; 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 explains how to specify and format measurements.

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 travellers will see on road signs, local maps, menus, food packages, weather reports, etc.

For most of the world, this is the.

However, for the United States of America, it's the "US standard" 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 UK, road distances are measured in miles and beer served by the pint, while meat and canned goods are measured in (kilo)grams. Milk is measured in both pints (in England and Wales) and litres (in Scotland). We favour accuracy over consistency.

The chief difference between the US system of units and the imperial system is in the sizes of the pint and the gallon. The US measures are 20% 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!

If the measurements span multiple countries,.

For articles that don't deal with a particular destination (like most travel topics),.

Provide conversions
It's easier for travellers to understand measurements if they're converted to their own familiar units. For this reason, it's best to provide conversions for measurements into both metric (SI) and US styles, the two systems most widely used in the English-speaking world.

If the preferred units are metric, try to provide US style measurements in parentheses afterwards. If the preferred units are US Standard, always provide metric measurements in parentheses afterwards.

If for some reason the local unit is neither metric nor US, try to provide first metric, then US (separated by a comma and a space) enclosed in the same parentheses afterwards.

Don't repeat conversions unnecessarily.

Accuracy
There is no need to convert between units to unnecessarily precise decimal places. If you convert between units only state the conversion to the same number of significant digits as the original measure. If you want to show decimal places or be more accurate than a single unit allows, consider going down to a smaller unit. Remember, these measurements are going to be used by travellers, not scientists.

To indicate, use the un-italicised abbreviation " " (followed by a space) rather than , , or.

Avoid orphaned units
Except for measurements of temperature, 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 (unless you're seriously underemployed)
 * 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 as

Decimal point and commas
In this, the English language version of Wikivoyage, a full stop or period should be used to separate any decimal fraction of a number from the integer part and never a comma, whatever the local practice is.

Similarly, don't 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 instead.

Examples
The following are some examples of good practice for measurements.
 * It's 815 km (506 mi) from Paris to Marseille.
 * It's 2,800 mi (4,500 km) from Los Angeles to New York City.
 * Mount Fuji is 3,776 m (12,388 ft) high.
 * In winter, Iqaluit gets down to -50°C (-58°F).
 * Temperatures in Death Valley routinely hit 110°F (43°C).
 * Just 3 km (2 mi) down the road in Hamburg you can get very good half-litres of beer.
 * Just 2 miles (3 km) down the road in Glasgow you can get very good pints of beer.
 * 5 km (3 mi) to the north is a national park. 5 km to the south is a lake.

Area
Always abbreviate units. Do not put periods (full stops) after units. Never use an "s" after a unit abbreviation to make it plural.


 * square millimetre:
 * square centimetre:
 * square metre:
 * square kilometre:
 * hectare:

Never capitalise the first letter.


 * square inch = in²
 * square foot = ft²
 * square yard = yd²
 * square mile = mi²
 * acre = acre

Duration
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. Never capitalize the first letter.


 * year or years:
 * week or weeks:
 * hour or hours:
 * minute or minutes:

Electrical

 * alternating current:
 * direct current:
 * ampere(s) or amp(s):
 * volt(s):
 * cycles per second:

Length
Always abbreviate units. Do not put periods (full stops) after units. Never use an "s" after a unit abbreviation to make it plural.


 * kilometre:
 * metre:
 * centimetre:
 * millimetre:

Note: Never capitalise the first letter.


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

Note: Never use single or double quotation marks ( or ) to signify feet or inches.

Spell in full, because some abbreviations, including "", conflict with abbreviations for other units.

Speed
Show as : or mph

eg:

Temperature

 * Celsius - "degrees Celsius" is allowed in prose or, more usually:

Note: Never use to mean Celsius!


 * Fahrenheit - "degrees Fahrenheit" is allowed in prose or, more usually: °F

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

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

Volume
Always abbreviate units. Do not put periods (full stops) after units. Never use an "s" after a unit abbreviation to make it plural.

Dry Volume

 * cubic metre:
 * cubic centimetre:
 * cubic millimetre:

Note: Never capitalise the first letter.


 * pint = pt
 * quart = qt
 * peck = pk
 * bushel = bu
 * cubic inch = in³ or cu in
 * cubic feet = ft³ or cu ft
 * cubic yard = yd³ or cu yd

Fluid Volume
Always abbreviate units. Do not put periods (full stops) after units. Never use an "s" after a unit abbreviation to make it plural.


 * liter:
 * milliliter:

( is always capitalised when used as an abbreviation for litre to avoid confusion with the numeral one.)


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

Weight/Mass
Always abbreviate units. Do not put periods (full stops) after units. Never use an "s" after a unit abbreviation to make it plural.


 * metric tonne:
 * kilogram:
 * gram:
 * milligram:

Note: Never capitalise the first letter.


 * ton = ton
 * hundredweight = cwt
 * pound = lb
 * ounce = oz