Speed Converter
Convert between mph, km/h, m/s, knots and Mach. As a quick guide, 100 km/h is about 62 mph.
Enter a value
Result
100 kilometres per hour =
62.1371 mph
100 × 0.621371 = 62.1371
1 mph = 1.609344 km/h exactly
Show the working
- 1. Convert 100 km/h to metre per seconds: 100 × 0.277778 = 27.7778.
- 2. Convert to mph: 27.7778 ÷ 0.44704 = 62.1371.
100 km/h in every unit
Typical speeds
- Walking
- 5 km/h
- Cycling
- 20 km/h
- Motorway limit (UK)
- 70 mph
- Speed of sound
- 1,235 km/h
Good to know: To convert m/s to km/h, multiply by 3.6.
About this tool
Convert speed between mph, km/h, knots, and meters per second — for driving, aviation, sailing, and sports.
Formula
1 mph = 1.609 km/h. 1 knot = 1.852 km/h. 1 m/s = 3.6 km/h.
Reference values
- 60 mph = 96.56 km/h
- 1 knot = 1.151 mph
- 1 m/s = 3.6 km/h
Questions people ask
How do I convert mph to km/h?
Multiply by 1.609344. For example, 60 mph is about 96.6 km/h.
How fast is a knot?
One knot is one nautical mile per hour, which is 1.852 km/h or about 1.151 mph.
What speed is Mach 1?
The speed of sound, which changes with temperature and altitude. This tool uses about 767 mph at sea level.
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How we calculate this
We use the standard published formula or definition for this calculation, and we show the working so you can check it. Source: NIST Special Publication 811, Guide for the Use of the International System of Units.
Spotted a mistake? Tell us and we'll check it. How we check our calculators