Speed Converter
Convert between common speed units including m/s, km/h, mph, knots, and ft/s.
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Result
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| Unit | Value |
|---|---|
Click a row to set it as the target unit.
Common Reference Speeds
| Description | km/h | mph | m/s |
|---|---|---|---|
| Walking | 5 | 3.1 | 1.39 |
| Cycling | 25 | 15.5 | 6.94 |
| Highway | 120 | 74.6 | 33.33 |
| Speed of Sound | 1,234 | 766.6 | 342.78 |
Click a row to load that speed.
Conversion Factors (base: m/s)
- 1 km/h = 1/3.6 m/s
- 1 mph = 0.44704 m/s
- 1 knot = 0.514444 m/s
- 1 ft/s = 0.3048 m/s
Frequently Asked Questions
How do I convert between km/h and mph?
Multiply km/h by 0.621 to get mph, or multiply mph by 1.609 to get km/h. For a quick estimate, halve the km/h value and add 10% (100 km/h ≈ 50 + 5 = 55 mph, actual: 62.1 mph). Alternatively, multiply km/h by 5/8.
What is a knot and where is it used?
One knot equals one nautical mile per hour (1.852 km/h or 1.151 mph). Knots are the standard speed unit in aviation and maritime navigation. The term comes from the old practice of counting knots on a rope pulled behind a ship to measure speed.
What is Mach number?
Mach number is the ratio of an object's speed to the speed of sound. Mach 1 equals the speed of sound (approximately 1,235 km/h or 767 mph at sea level). Mach 2 is twice the speed of sound. The value varies with altitude and temperature because the speed of sound changes.