Speed Converter
Convert speed between mph, km/h, m/s and knots. Enter a value, choose the starting unit and select the unit you need.
How to use this calculator
- Enter the speed you want to convert.
- Select the unit the speed is currently measured in.
- Choose the unit you want to convert it to.
- The converted speed updates automatically as you type or change either unit.
Every option shows the name and the symbol, so Miles per hour (mph) and Metres per second (m/s) are never mixed up. The read-out under the inputs shows each selected unit's exact size in metres per second, and Max decimal places keeps every significant digit for a small conversion.
How speed conversion works
The calculator first converts your selected speed into metres per second, then converts that value into your chosen unit.
- 1 mph = 0.44704 m/s
- 1 km/h = 0.277778… m/s (exactly 1 ÷ 3.6)
- 1 knot = 0.514444… m/s (one nautical mile per hour)
Example: convert 60 mph to km/h
- 60 × 0.44704 = 26.8224 m/s
- 26.8224 ÷ (1 ÷ 3.6) = 96.56064 km/h
That is the same as multiplying by 1.609344 directly: 60 mph × 1.609344 = 96.56064 km/h.
Common speed conversions
| Miles per hour | Kilometres per hour | Metres per second | Knots |
|---|---|---|---|
| 1 mph | 1.61 km/h | 0.45 m/s | 0.87 kn |
| 10 mph | 16.09 km/h | 4.47 m/s | 8.69 kn |
| 20 mph | 32.19 km/h | 8.94 m/s | 17.38 kn |
| 30 mph | 48.28 km/h | 13.41 m/s | 26.07 kn |
| 40 mph | 64.37 km/h | 17.88 m/s | 34.76 kn |
| 50 mph | 80.47 km/h | 22.35 m/s | 43.45 kn |
| 60 mph | 96.56 km/h | 26.82 m/s | 52.14 kn |
| 70 mph | 112.65 km/h | 31.29 m/s | 60.83 kn |
Values in this table are rounded for readability. The calculator uses full conversion precision.
Useful speed conversion facts
| Conversion | Equivalent |
|---|---|
| 1 mph | 1.609344 km/h |
| 1 mph | 0.44704 m/s |
| 1 km/h | 0.621371 mph |
| 1 m/s | 3.6 km/h |
| 1 knot | 1.852 km/h |
| 1 knot | approximately 1.15078 mph |
| 1 knot | approximately 0.514444 m/s |
| 1 ft/s | 0.3048 m/s |
What is a knot?
A knot is one nautical mile per hour, used for the speed of ships and aircraft. One nautical mile is 1,852 metres, so a knot is 1.852 km/h, about 1.15078 mph or 0.514444 m/s. Wind speed in marine and aviation forecasts is usually given in knots for the same reason.