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If you are comparing other units, you can continue from here.
How to convert a speed
Enter a speed in the unit you know and we will calculate the other four conversions.
- 1Enter the speed you want to convert.
- 2Choose m/s, km/h, mph, ft/s or knots.
- 3Check the equivalents. You can also edit any row and convert from that unit.
Speed guide
The same speed, five ways to write it
You are driving at 100 km/h, cross into a country that uses miles, and suddenly see 62.1 mph. Do not worry: you did not slow down. Only the unit changed. The same happens with meters per second, feet per second and knots. This converter puts all those ways of expressing speed side by side.
km/h, mph, m/s... why so many?
Not everyone measures speed in the same way or for the same purpose. Kilometers per hour (km/h) are common on roads in many countries. In the United States and the United Kingdom, miles per hour (mph) are more familiar.
Meters per second (m/s) appear often in physics and weather reports. Feet per second (ft/s) are used in some technical settings. Knots are especially common in marine navigation and aviation. One knot means one nautical mile per hour. Yes, it is a different mile.
The number changes. The speed does not.
Here is the part that can be confusing: a larger number does not necessarily mean a faster speed when you compare different units. For example, 100 km/h is about 62.1 mph, 27.8 m/s, 91.1 ft/s or 54 knots. Five quite different numbers for exactly the same motion.
Results show up to one decimal place so you do not end up reading a long row of digits. Calculations use the value you entered and round each equivalent only for display.
Common conversions: km/h to mph and more
These are a few everyday searches: 100 km/h is about 62.1 mph; 60 mph is about 96.6 km/h; and 10 m/s equals 36 km/h.
Enter any of those values to also get feet per second and knots. The tool uses the exact conversion factor and rounds only the displayed result.
Conversion factors
- Kilometers per hour to meters per second
- m/s = km/h ÷ 3.6
- Miles per hour to kilometers per hour
- km/h = mph × 1.609344
- Knots to kilometers per hour
- km/h = knots × 1.852
- Feet per second to meters per second
- m/s = ft/s × 0.3048
The calculation runs in your browser
Conversions are calculated directly in your browser. You do not need an account, and the value you entered never has to be sent to a server.
Speed questions
Can I convert a speed of zero?
Of course. Zero is still zero when you change units. With no movement, you will have 0 km/h, 0 mph, 0 m/s, 0 ft/s and 0 knots.
Are negative speeds accepted?
No. This converter works with speed as a magnitude, so the value must be zero or greater. If you also need a direction, you are describing a velocity vector and need more than a minus sign.
What is the difference between mph and knots?
Both measure distance per hour, but they use different miles. A land mile is exactly 1.609344 km and a nautical mile is 1.852 km. That is why 1 mph and 1 knot are not the same speed.
Does the decimal comma work?
Yes. You can enter 12.5 or 12,5. We understand both as the same value, so you do not have to fight your keyboard.
How much is 100 km/h in mph?
100 km/h is approximately 62.1371 mph. Enter 100 in the km/h row to see every equivalent.
How do I convert mph to km/h?
Multiply mph by 1.609344. You can also enter the value directly in the mph row and let the converter do the calculation.