# SI units

From OpenStreetMap Wiki

All numbers by now are given in SI units and derived numbers.

- length: m (metres), km (1 km = 1000 m)
- time: s (seconds), h (hours)
- weight: kg (kilogramm), t (ton; 1 t = 1000 kg)

Numbers within countries that do not use SI units, such as maxspeed=30 **mph** (miles per hours) may use the local system for all entries of this country, including the unit name (mph, ft, ...). This will be converted to km/h or m.

The recommended number formatting is:

- decimal separator: "." (point)
- thousands separator: " " (space)