We often have to use measurements in Wikitravel — 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.
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 most of the world, this is the metric system. For the United States of America, it's the "US standard" system (miles, gallons, pounds), which is similar to 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. Milk is measured in both pints and litres. We favor accuracy over consistency.
The chief difference between the US standard system and the Imperial system is in the sizes of the pint and the gallon. The Imperial measures are 25% larger than the US measures. That means you get more drunk on a British pint, and you get more miles to the gallon on British roads!
If the measurement spans multiple countries, use metric.
For articles that don't deal with a particular destination (like travel topics), use metric.
It's easier for travelers to understand measurements if they're converted to their own country's units. For this reason, it's best to provide conversions for measurements into both metric and imperial, the two systems most widely used in the English-speaking world.
If the preferred units are metric, provide imperial measurements in parentheses after. If the preferred units are imperial, provide metric measurements in parentheses. If for some reason the local unit is neither metric nor imperial, provide first metric then imperial in parentheses afterwards.
Don't repeat conversions unnecessarily.
There is no need to convert between units to the nth decimal place. 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.
The following are some examples of good practice for measurements.