Kph to mph converter, kilometres per hour in miles per hour.

To convert kph to mph, multiply by 0.621371. So 100 km/h is 62.14 mph, 50 km/h is 31.07 mph and 120 km/h is 74.56 mph. Kph, km/h and kmh all mean kilometres per hour.

How to use the converter

1. Type the amount in the Kilometers per hour (km/h) box. A decimal such as 2.5 or a fraction such as 3/4 works.
2. The big result shows Miles per hour (mph). Use Decimals in the side column to fix the number of places.
3. The cards under the result give the same speed in other units.
4. Type in the second box, or press the swap button, to convert miles per hour to kilometers per hour instead.
5. Click a row in Common values to load it. Copy result, Copy link, Copy table and Print chart keep the answer. Start again resets the box.

The factor, worked out

NIST lists 1 mile per hour as exactly 1.609344 km/h. Turn it around: 1 km/h = 1 ÷ 1.609344 = 0.621371 mph.

The 5/8 shortcut

Five eighths is 0.625, close to 0.6214. Divide by 8 and multiply by 5. For 80 km/h: 80 ÷ 8 = 10, 10 × 5 = 50 mph. The true figure is 49.71 mph, so the shortcut runs 0.6 percent high. Even closer: take 60 percent and add a little. 80 × 0.6 = 48, plus 1.7 = 49.7.

Kph to mph, 20 to 160

Worked examples

• A limit of 30 km/h. 18.64 mph.
• A limit of 110 km/h. 68.35 mph.
• A bike at 25 km/h. 15.53 mph.
• A 90 km/h car for 2 hours. 180 km, which is 55.92 mph for 2 hours or 111.8 miles.
• Back the other way. 65 mph = 104.6 km/h.

Treadmill and running pace

A treadmill may show km/h while a road sign shows mph, and a runner thinks in minutes per mile or per kilometre. The Treadmill or running pace box turns a speed into both. Pace in minutes is 60 divided by the speed, so 10 km/h is 6:00 per km and 9:39 per mile, and 6 mph is 10:00 per mile and 6:13 per km. It also gives the time for 1 mile, 5 km and 10 km at that pace.

Where the numbers come from

NIST SP 811, Appendix B.8 lists the international mile as 1,609.344 m, the nautical mile as 1,852 m, and the knot as one nautical mile per hour (0.5144444 m/s). It also gives 1 mile per hour as 1.609344 km/h. Checked 24 Oct 2026. The converter keeps these as exact fractions and rounds only the last digit shown.

Mistakes to avoid

Do not use 1.6 the wrong way. 1.6 is for mph to km/h. Going from km/h to mph, the number gets smaller, so your answer should be about 62 percent of what you typed. Also remember a speed limit sign in one country is in the unit of that country, so check the unit before you convert.

Related pages: Mph to kph, Km to miles, and Knots to mph.