About the MPH to KM/H Converter
This MPH to KM/H converter turns a speed in miles per hour into kilometers per hour using the exact international definition of the mile (1 mile = 1.609344 km). Type any speed and you also get meters per second, knots and feet per second, so one entry covers road, science and marine uses.
It is handy for drivers renting a car abroad, travellers reading a US speed limit sign, runners and cyclists comparing training data, and anyone reading a car review that quotes top speed or 0–60 figures in a different unit. The reference table shows common speed limits side by side, which makes mental conversion easier.
Because the factor is exact, results are precise to as many decimals as you need. A quick rule of thumb is to multiply mph by 1.6, which is accurate to within about 0.6%.
With the default inputs, the kilometers per hour is 96.56 km/h. Change any value above to recalculate instantly.
How to use the mph to km/h converter
- 1Enter the speed in miles per hour.
- 2Read the km/h result at the top — it updates as you type.
- 3Check m/s, knots and ft/s if you need a scientific or marine unit.
- 4Use the table to look up common speed limits at a glance.
Formula and method
Since the 1959 international yard and pound agreement, one mile is defined as exactly 1,609.344 meters, so one mile per hour is exactly 1.609344 kilometers per hour. Multiply the speed in mph by 1.609344 to get km/h; divide km/h by 1.609344 to go back.
Meters per second are km/h ÷ 3.6 (1 mph = 0.44704 m/s exactly), knots are km/h ÷ 1.852 because a nautical mile is 1,852 m, and feet per second are mph × 5280 ÷ 3600. The pace output is 60 ÷ km/h, the minutes needed to cover one kilometer.
- mph
- Speed in miles per hour
- km/h
- Speed in kilometers per hour
- 1.609344
- Kilometers in one international mile (exact)
Worked examples
60 mph highway speed
60 × 1.609344 = 96.56 km/h. The same speed is 26.82 m/s and exactly 88 feet per second, which is why 60 mph is often described as "88 feet every second".
25 mph school or residential zone
25 × 1.609344 = 40.23 km/h, so a US 25 mph zone is almost identical to a European 40 km/h limit.
70 mph UK motorway limit
70 mph is 112.65 km/h — slightly faster than a 110 km/h limit. At that speed a kilometer passes in about 32 seconds (0.53 minutes).
Frequently asked questions
How do I convert mph to km/h?+
Multiply the speed in mph by 1.609344. For example, 50 mph × 1.609344 = 80.47 km/h. For quick mental math, multiply by 1.6 or add 60% to the mph figure.
Is 100 km/h the same as 60 mph?+
Close but not identical. 100 km/h is 62.14 mph and 60 mph is 96.56 km/h, so 100 km/h is about 3.6% faster. Car reviews often treat 0–60 mph and 0–100 km/h as similar benchmarks.
What is the difference between km/h and kph?+
None. km/h is the official SI-style symbol and kph is an informal abbreviation for the same unit, kilometers per hour. Both convert from mph with the same factor.
How fast is 1 mph in meters per second?+
One mile per hour is exactly 0.44704 m/s. To convert km/h to m/s divide by 3.6, and to convert m/s back to mph divide by 0.44704.
Do UK road signs use mph or km/h?+
The UK and the US post speed limits in miles per hour, while almost every other country, including Ireland and Canada, uses kilometers per hour.