Kilometres per hour to Miles per hour — km/h to mph

Enter a value to convert kilometres per hour (km/h) to miles per hour (mph). Works in your browser with no sign-up.

[ km/h / mph — Speed ] instant · works offline
Kilometres per hour · km/h
0.6213712
Miles per hour · mph
1 km/h = 0.6213712 mph
Kilometres per hour → Miles per hour
⇄ Reverse: Miles per hour → Kilometres per hour
Formula

1 km/h = 0.6213712 mph

Multiply the number of kilometres per hour by 0.6213712 (or divide by 1.609344). For example, 40 km/h × 0.6213712 = 24.85485 mph.

Quick Reference — Kilometres per hour to Miles per hour
About Speed Units

Kilometres per hour is the road-speed unit in most countries; the US and UK use miles per hour. Knots (one nautical mile per hour) are used at sea and in aviation. Mach expresses speed as a multiple of the speed of sound, which depends on air temperature; this converter uses 340.3 m/s, the value for the standard atmosphere at sea level (15 °C).

Related Conversions
mph → km/h km/h → kn km/h → Mach m/s → mph kn → mph All speed units
All Speed Conversions
→Knots to kilometres per hour →Mach to kilometres per hour →Metres per second to miles per hour →Miles per hour to kilometres per hour →Metres per second to kilometres per hour →Knots to miles per hour →Kilometres per hour to knots →Miles per hour to metres per second →Kilometres per hour to Mach
FAQ — Kilometres per hour to Miles per hour

How do I convert kilometres per hour to miles per hour?

Multiply the number of kilometres per hour by 0.6213712 (or divide by 1.609344). For example, 40 km/h × 0.6213712 = 24.85485 mph.

How many miles per hour are in one kilometre per hour?

1 kilometre per hour = 0.6213712 mph (shown to up to 7 significant figures).

What is Mach 1 in km/h?

In the standard atmosphere at sea level (15 °C) the speed of sound is about 340.3 m/s, which is about 1,225 km/h or 761 mph. It is lower in colder air, so at typical airliner cruising altitude it is closer to 1,060 km/h.

Does this converter work offline?

Yes. Once the page has loaded, conversions run entirely in your browser and nothing is sent to a server.