π¨ Speed Converter
Convert between mph, km/h, m/s, ft/s, and knots, live as you type.
Converted Speed
How to Use This Converter
Type a speed, choose the unit it is in and the unit you want, and the result updates the instant you type. Road, track, water, and air units are all here.
Enter the speed in the Speed box, for example 65 or 10.5.
Pick the From unit: mph, km/h, m/s, ft/s, or knots.
Pick the To unit. The converted value appears immediately at the top of the results card.
Scan the all-unit table under the result to see the same speed in every other unit at a glance.
Exact Conversion Factors
Because the mile is defined as exactly 1.609344 kilometers, mph-to-km/h conversions are exact. Meters per second ties to km/h through the clean factor of 3.6, which is why physicists love it. The knot is exactly 1.852 km/h by definition of the nautical mile. For quick mental math, mph to km/h: multiply by 1.6; km/h to mph: multiply by 0.62; m/s to mph: multiply by 2.24; mph to m/s: multiply by 0.447. Cyclists remember 36 km/h = 10 m/s = 22.4 mph as the magic triple.
Worked Example
The highway sign says 65 mph and your rental car shows km/h. 65 x 1.609344 = 104.607 km/h. A runner clocks 10 m/s on a sprint drill: 10 x 2.2369363 = 22.369 mph, and 10 x 3.6 = 36 km/h. A sailboat making 12 knots: 12 x 1.1507794 = 13.809 mph, or 12 x 1.852 = 22.224 km/h. Try each in the converter and check the all-unit table for the rest.
Where This Comes Up
Driving is the obvious one: US cars show mph while most of the world shows km/h, and rental cars in Europe or Canada make the conversion daily. Runners and cyclists live between min/mile pace, km/h, and m/s depending on the training app. Boaters and pilots think in knots, since navigation charts and weather reports use them. Weather reports give wind in mph in the US and km/h elsewhere, and storm chasers add m/s. Physics classes insist on meters per second, so every homework problem is a conversion exercise.
Frequently Asked Questions
How many km/h is 100 mph?
160.934 km/h. The exact factor is 1.609344 km per mile, so multiply any mph value by 1.60934. For a quick estimate, multiply by 1.6 and add a touch.
How many mph is 100 km/h?
62.137 mph. The exact factor is 0.621371 miles per kilometer, so multiply km/h values by 0.6214. That is why 120 km/h speed limits feel like about 75 mph.
What is a knot in mph?
1 knot equals 1.15078 mph, or 1.852 km/h exactly. A knot is one nautical mile per hour, defined as 1,852 meters per hour. Boats and aircraft use knots because they tie directly to charts: one minute of latitude equals one nautical mile.
How fast is 10 m/s in mph?
22.369 mph. Multiply m/s by 2.23694 to get mph, or by 3.6 to get km/h. So 10 m/s equals 36 km/h, a fast cycling pace, and a 100 m sprinter at 10 m/s covers the distance in exactly 10 seconds.
How do I convert pace (min/mile) to speed?
Divide 60 by the pace in minutes per mile. A 10 min/mile pace is 60 / 10 = 6 mph. An 8 min/mile pace is 7.5 mph, and a 6 min/mile pace is 10 mph. For km/h, divide 60 by min/km instead: 5 min/km equals 12 km/h.