Converters
Convert speed between kilometres per hour, metres per second, miles per hour, and knots — type a value and see all four units at once.
Results update as you type. No calculate button. All calculations run locally in your browser.
—
—
| Unit | Value |
|---|
All four units describe the same speed; the mile and knot factors below are exact definitions.
Convert the source value to metres per second, then divide by the target unit's m/s factor: target = value × source factor ÷ target factor.
| Unit | Metres per second per unit |
|---|---|
| Kilometre per hour (km/h) | 0.2777777778 (1/3.6) |
| Metre per second (m/s) | 1 |
| Mile per hour (mph) | 0.44704 |
| Knot (kn) | 0.5144444444 (1852/3600) |
1 mph = 0.44704 m/s exactly (from 1 mile = 1,609.344 m). 1 knot = 1 nautical mile per hour = 1,852 m per hour, exactly.
100 km/h = 100 × (1/3.6) = 27.777778 m/s, and 27.777778 ÷ 0.44704 = 62.137119 mph. The same speed is 27.777778 ÷ 0.5144444444 = 53.995680 knots.
Negative speeds are rejected as invalid (direction is not modelled; use a signed value only if you track direction yourself). Display values are rounded to 6 decimal places; the underlying calculation is not rounded.
62.137119 mph — the worked example above shows each step.
One nautical mile per hour. A nautical mile is exactly 1,852 m, so 1 knot = 0.5144444444 m/s. It is the standard unit at sea and in aviation.
Because the mile (1,609.344 m) and the hour do not divide evenly: 1,609.344 ÷ 3,600 = 0.44704 m/s exactly.
Approximately: the exact factor is 0.6213711922. Multiplying by 0.62 gives 62 mph for 100 km/h — close, but 0.137 mph low.
No — pace is the inverse of speed and needs its own calculation. This page converts speed units only.
Results are estimates only and do not constitute professional advice.