km/h to mph converter
This calculator converts km/h to mph: 100 km/h is 62.14 mph, and 1 mph is exactly 1.609344 km/h. Meters per second, knots and feet per second convert instantly too – handy for speed limits in the US and UK.
Example: Speed 100 · from: Kilometers per hour (km/h) · to: Miles per hour (mph) → Result: 100 km/h = 62.137 mph. Source: NIST SP 811, Appendix B.8 – factors for units listed alphabetically. Updated: .
How it is calculated
km/h to mph: the formula
mph = km/h × 0.621371, or km/h ÷ 1.609344. In reverse, km/h = mph × 1.609344. As a rule of thumb: mph × 1.6 = km/h and km/h × 0.6 = mph.
- 50 km/h = 31.07 mph
- 100 km/h = 62.14 mph
- 130 km/h = 80.78 mph
- 60 mph = 96.56 km/h
Where the factor comes from
The international mile has been exactly 1,609.344 m since 1959 (1 mph = 1,609.344 m per hour = 0.44704 m/s). One kilometer per hour is 1/3.6 m/s. Both definitions together give the factor 1.609344 without rounding.
Where mph is used
In the US and the UK, speed limits and speedometers use mph; most other countries use km/h. Shipping and aviation use the knot (1 kn = 1.852 km/h = 1.1508 mph).
Extras: travel time and running pace
Below the result you see how long 100 km takes at that speed. For running speeds up to 45 km/h the calculator also shows the pace in minutes per kilometer, for example 12 km/h = 5:00 min/km.
Honest limits
The calculator only converts units. For speedometer error, wind or current, the reading on the vehicle or GPS device counts, not the conversion.
Frequently asked questions
How many mph is 100 km/h?
100 km/h is 62.14 mph. 50 km/h is 31.07 mph and 130 km/h is 80.78 mph.
How do I convert km/h to mph?
Multiply the kilometers per hour by 0.621371: 80 km/h × 0.621371 = 49.71 mph. As a rule of thumb, × 0.6 works.
How many km/h is 60 mph?
60 mph is 96.56 km/h. Rule of thumb: mph × 1.6.
How many km/h is 1 knot?
1 knot is 1.852 km/h or 0.5144 m/s.
How do I convert m/s to km/h?
Multiply meters per second by 3.6: 10 m/s × 3.6 = 36 km/h.
Sources and legal basis
- NIST SP 811, Appendix B.8 – factors for units listed alphabetically
- BIPM – SI Brochure, Table 8: non-SI units accepted for use with the SI (bar, conventional mmHg, nautical mile, hectare)
As of:
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