Speed converter
Kilometers per hour, miles per hour, knots, m/s and ft/s, converted as you type.
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Raw value:
In every unit
| Unit | Value |
|---|---|
| Meter per second (m/s) | – |
| Kilometer per hour (km/h) | – |
| Mile per hour (mph) | – |
| Knot (kn) | – |
| Foot per second (ft/s) | – |
kB, MB, GB and TB are decimal (1 kB = 1000 B), as on drive labels and mobile plans. KiB, MiB, GiB and TiB are binary (1 KiB = 1024 B), as Windows shows file sizes. Bits are for connection speeds; 8 bits make a byte.
A month is the average Gregorian month of 30.436875 days and a year is 365.2425 days; calendar months and years vary.
US units follow the US customary system (1 gal = 3.785 L, 1 cup = 236.6 mL); UK units follow the imperial system (1 gal = 4.546 L).
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Speed conversions come up when you drive a rental car whose speedometer is in the other unit, read a weather report where the wind is in knots or meters per second, or compare a running speed in km/h with a treadmill in mph. Type the speed, choose the units and the result appears as you type; the table lists the same speed in all five units, so 130 km/h reads as 80.78 mph, 70.19 kn and 36.11 m/s together. The factors are exact because they derive from the mile of 1609.344 m and the nautical mile of 1852 m. The page works offline and sends nothing.
How to use
- Type the speed, for example 130.
- Pick the unit you have and the unit you want; km/h to mph is preset.
- Swap them to go from mph to km/h.
- Read knots, m/s or ft/s in the table.
What it handles
- Five units: meter per second, kilometer per hour, mile per hour, knot and foot per second.
- Exact factors: 1 mph = 1.609344 km/h, 1 kn = 1.852 km/h, 1 m/s = 3.6 km/h.
- Gives speed, not pace; the FAQ explains how to get minutes per kilometer from km/h.
- A decimal comma or a point both work, so 8,5 and 8.5 km/h give the same mph.
FAQ
How do I convert km/h to mph in my head?
Multiply by 0.6 for a quick estimate, or by 5/8 for a closer one: 100 km/h is 62 mph, 130 km/h is 81 mph, 50 km/h is 31 mph. Going the other way, multiply mph by 1.6: 70 mph is 113 km/h. Common speed limits: 30 mph is 48 km/h, 60 mph is 97 km/h, 120 km/h is 75 mph.
What is a knot?
One nautical mile per hour, which is 1.852 km/h or 1.151 mph. Ships, aircraft and marine weather forecasts use knots because the nautical mile matches a minute of latitude on a chart. A wind of 20 knots is 37 km/h, a fresh breeze; 34 knots and above is gale force.
How do I turn km/h into running pace?
Divide 60 by the speed in km/h to get minutes per kilometer: 10 km/h is 6:00 min/km, 12 km/h is 5:00 min/km, 8.5 km/h is 7:04 min/km (7.06 minutes; multiply the fraction by 60 for the seconds). For minutes per mile, first convert to mph and divide 60 by that: 6.2 mph is 9:41 min/mile.
How does m/s relate to km/h?
Multiply by 3.6: a wind of 10 m/s is 36 km/h. Weather services in many countries give wind in m/s, and the Beaufort scale is defined in them, so 10.8 to 13.8 m/s is force 6. Dividing km/h by 3.6 goes back, which is handy for physics homework where everything is in meters and seconds.
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