Speed Converter
Convert mph to kph, knots to mph, m/s to mph and more. Free instant speed converter.
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All units
| Unit | Value | Copy |
|---|---|---|
| Meters per Secondm/s | 26.8224 | |
| Kilometers per Hourkm/h | 96.56064 | |
| Miles per Hourmph | 60 | |
| Knotskn | 52.138575 | |
| Feet per Secondft/s | 88 | |
| Mach (sea level)Mach | 0.078822181 |
Popular conversions
How speed conversion works
Speed is a distance divided by a time, so every speed unit is a length unit over a time unit. This page stores each one in meters per second. A mile per hour is exactly 0.44704 m/s (1,609.344 m ÷ 3,600 s), a kilometer per hour is 1/3.6 m/s, and a knot is one nautical mile (1,852 m) per hour, about 0.5144 m/s.
To convert, the tool multiplies by the source unit's value in m/s and divides by the target's. Mach is not a fixed speed: it is a ratio to the local speed of sound, so the Mach row uses the sea-level standard value of 340.29 m/s and is only a rough guide at altitude.
Worked examples
Driving abroad, km/h to mph
A 100 km/h limit is 100 ÷ 1.609344 = 62.14 mph. Multiplying by 0.6 gives 60 mph, close enough to read a sign.
Boating, knots to mph and km/h
30 knots × 1.852 = 55.56 km/h, or 34.52 mph. Knots are a little faster than mph: multiply by 1.15.
Physics homework, mph to m/s
60 mph × 0.44704 = 26.82 m/s, which is also 88 ft/s. That 60 mph = 88 ft/s identity is exact and handy for stopping-distance questions.
Speed limits and everyday speeds
| mph | km/h | m/s | kn | |
|---|---|---|---|---|
| Walking pace (example) | 3 | 4.82803 | 1.34112 | 2.60693 |
| School zone (US, example) | 20 | 32.1869 | 8.9408 | 17.3795 |
| Urban limit (example) | 30 | 48.2803 | 13.4112 | 26.0693 |
| Highway (US, example) | 55 | 88.5139 | 24.5872 | 47.7937 |
| Motorway limit (UK) | 70 | 112.654 | 31.2928 | 60.8283 |
| Train at 125 mph (example) | 125 | 201.168 | 55.88 | 108.622 |
Common mistakes
- Using 1.6 when the number matters. 1 mph is exactly 1.609344 km/h (NIST SP 811). The 0.6% error from 1.6 adds up on long trips or in calculations.
- Confusing knots with nautical miles. A knot is already a speed (nautical miles per hour), so 'knots per hour' is not a unit.
- Mixing up km/h and m/s by a factor of 3.6. 10 m/s is 36 km/h, not 10 km/h. Multiply m/s by 3.6 for km/h.
- Treating Mach as a constant. Mach 1 is slower in cold, high air than at sea level, so converting Mach to mph only gives a sea-level estimate.
Sources
Conversion charts
Frequently asked questions
How fast is 1 mph in km/h?
1 mph equals about 1.609 km/h.
How many knots is 100 mph?
100 mph equals about 86.9 knots.
What are common speed limits in km/h?
20 mph = 32.2 km/h, 25 mph = 40.2 km/h, 30 mph = 48.3 km/h, 40 mph = 64.4 km/h, 50 mph = 80.5 km/h, 55 mph = 88.5 km/h, 60 mph = 96.6 km/h, 65 mph = 104.6 km/h, 70 mph = 112.7 km/h and 80 mph = 128.7 km/h (1 mph = 1.609344 km/h exactly).
What are common km/h speed limits in mph?
30 km/h = 18.6 mph, 50 km/h = 31.1 mph, 60 km/h = 37.3 mph, 80 km/h = 49.7 mph, 90 km/h = 55.9 mph, 100 km/h = 62.1 mph, 110 km/h = 68.4 mph, 120 km/h = 74.6 mph and 130 km/h = 80.8 mph.
How do I convert mph to km/h in my head?
Multiply by 1.6 for a close answer (60 mph × 1.6 = 96 km/h; the exact figure is 96.6). For km/h to mph, multiply by 0.6 or divide by 1.6 (100 km/h ≈ 62 mph).
How do I convert m/s to km/h?
Multiply by 3.6, because one metre per second covers 3,600 metres in an hour. 10 m/s = 36 km/h, which is about 22.4 mph.
How many mph is one knot?
1 knot is one nautical mile (1,852 m) per hour, which is about 1.151 mph or 1.852 km/h.
How fast is Mach 1 in mph?
At sea level in the standard atmosphere, Mach 1 is about 340.3 m/s, which is about 761 mph or 1,225 km/h. The speed of sound falls as air gets colder, so Mach 1 at cruising altitude is slower in mph.
How many feet per second is 60 mph?
Exactly 88 ft/s, because 60 miles is 316,800 ft and an hour is 3,600 s.
How do I convert a running pace to speed?
Divide 60 by the minutes per unit. A 5:00 per km pace is 60 ÷ 5 = 12 km/h, which is 7.46 mph.