Kilometers per Hour ⇄ Miles per Hour Converter

How to convert kilometers per hour to miles per hour

To convert kilometers per hour to miles per hour, divide the value by 1.609344, or multiply it by about 0.621371.

mph = km/h ÷ 1.609344

Example: 10 km/h ÷ 1.609344 = 6.21371 mph

How to convert miles per hour to kilometers per hour

To convert miles per hour to kilometers per hour, multiply the value by 1.609344.

km/h = mph × 1.609344

Example: 10 mph × 1.609344 = 16.0934 km/h

1 km/h = 0.621371 mph · 1 mph = 1.60934 km/h

One mile per hour is exactly 1.609344 kilometers per hour. For a quick estimate in your head, multiply km/h by 0.6 to get mph, or multiply mph by 1.6 to get km/h.

Speed units around the world

Road speeds are posted in kilometers per hour in most countries. The United States and the United Kingdom post limits in miles per hour, and cars sold there show mph as the main speedometer scale, usually with km/h in smaller numbers. Other fields have their own units: ships and aircraft use knots, science uses meters per second, and weather services give wind speed in km/h, mph, m/s or knots depending on the country.

Speed limits side by side

Limits are set in round numbers of the local unit, so a “matching” limit abroad is never exactly the same:

When you drive abroad in a rental car, the speedometer’s second scale is the easiest check. If it only shows one unit, memorize a few anchor pairs and scale from them: 50 km/h ≈ 31 mph, 100 km/h ≈ 62 mph and 120 km/h ≈ 75 mph; 30 mph ≈ 48 km/h and 60 mph ≈ 97 km/h.

Meters per second and knots

One meter per second is 3.6 km/h, because an hour has 3,600 seconds. One mph is exactly 0.44704 m/s, so 1 m/s is about 2.24 mph. A knot is one nautical mile per hour: exactly 1.852 km/h, or about 1.15 mph.

Walking, cycling and treadmills

A typical walking pace of about 5 km/h is 3.1 mph, and a relaxed bike ride at 20 km/h is 12.4 mph. Treadmills in the US usually show mph: 6.0 mph is 9.7 km/h, which is exactly a 10-minute mile. For running pace per kilometer or per mile, see km to miles.

Common mistakes

• Treating knots as mph. A boat doing 30 knots is going 34.5 mph, or 55.6 km/h.
• Assuming 100 km/h equals 60 mph. 100 km/h is 62.1 mph, and 60 mph is 96.6 km/h. The 3.4 km/h gap is small, but it can decide whether you are at a limit or over it.
• Writing “kph” in formal text. It is understood everywhere, but the official symbol is km/h.

FAQ

Is 0–100 km/h the same as 0–60 mph?

No. 100 km/h is 62.1 mph, so a car’s 0–100 km/h time is slightly longer than its 0–60 mph time.

How fast is 100 mph in km/h?

160.9 km/h.

How do I read a wind forecast given in m/s?

Multiply by 3.6 for km/h or by about 2.24 for mph. A 12 m/s wind is 43 km/h or 27 mph, a “strong breeze” (force 6) on the Beaufort scale.

How fast is a 300 km/h high-speed train in mph?

About 186 mph, or 83.3 meters per second.

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