How to Convert Kilometres per hour to Metres per second (km/h to m/s)
Speed conversions come up with expressway limits in km/h, foreign car specs in mph and wind speeds reported in knots by the Meteorological Service. This guide shows how to convert kilometres per hour into metres per second by hand, with examples and a quick-reference table.
The conversion
To convert kilometres per hour to metres per second, multiply the value by 0.2777777778. To go the other way, divide by the same number (or multiply by 3.6). For a quick estimate, multiply by about 0.28.
Metres per second = kilometres per hour × 0.2777777778
Worked examples
- 3 km/h = 0.833333 m/s
- 12.5 km/h = 3.4722 m/s
- 75 km/h = 20.8333 m/s
Kilometres per hour to Metres per second table
| Kilometres per hour | Metres per second |
|---|---|
| 1 km/h | 0.277778 m/s |
| 2 km/h | 0.555556 m/s |
| 5 km/h | 1.3889 m/s |
| 10 km/h | 2.7778 m/s |
| 20 km/h | 5.5556 m/s |
| 25 km/h | 6.9444 m/s |
| 50 km/h | 13.8889 m/s |
| 100 km/h | 27.7778 m/s |
| 250 km/h | 69.4444 m/s |
| 500 km/h | 138.8889 m/s |
| 1,000 km/h | 277.7778 m/s |
Common questions
Is km/h to m/s exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Metres per second to Kilometres per hour converter.
Mistakes to avoid
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Background
Many conversion factors are exact by definition. The inch has been defined as exactly 2.54 centimetres since 1959, and the pound as exactly 0.45359237 kilograms, so conversions involving them can be as precise as you need.
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
For any value, use the Kilometres per hour to Metres per second Converter or browse all speed converters.
Run your own numbers: Kilometres per hour to Metres per second Converter