About the Speed Converter
This speed converter shows a speed in mph, km/h, m/s, knots, ft/s, km/s and Mach at once. Use it for speed limits when driving abroad, wind speeds, boating and aviation in knots, or physics homework. The running pace card turns minutes per mile into mph and predicts 5K, 10K, half-marathon and marathon times.
How to use
- Type a speed in the top box and choose its unit.
- Choose the unit you want below; typing in the bottom box converts backwards.
- Tap a popular conversion such as 60 mph or 20 knots.
- For running, enter your pace per mile (minutes and seconds) or your speed in mph.
Speed conversion chart
| Unit | Equals |
|---|---|
| 1 km/h | 0.2778 m/s · 0.6214 mph |
| 1 m/s | 3.6 km/h · 2.2369 mph |
| 1 mph | 1.609344 km/h · 0.44704 m/s |
| 1 kn | 1.852 km/h · 1.1508 mph |
| Mach 1 | ≈ 1225 km/h · 761 mph |
Common speed limits: mph to km/h
| mph | km/h |
|---|---|
| 25 mph | 40 km/h |
| 35 mph | 56 km/h |
| 55 mph | 89 km/h |
| 65 mph | 105 km/h |
| 70 mph | 113 km/h |
| 75 mph | 121 km/h |
FAQ
How do I convert mph to km/h?
Multiply by 1.609344. 60 mph × 1.609344 ≈ 96.6 km/h. To go from km/h to mph, multiply by 0.6214.
What is a knot?
A knot is one nautical mile (1,852 m) per hour, about 1.15 mph or 1.852 km/h. It is used at sea and in aviation.
How fast is Mach 1?
Mach 1 is the speed of sound. At sea level and 15 °C it is about 340.3 m/s, or roughly 761 mph. It gets lower at high altitude where the air is colder.
What pace do I need for a sub-4-hour marathon?
About 9:09 per mile (5:41 per km), which is roughly 6.6 mph.