Speed converter
Enter a speed and pick its unit — you’ll see it in miles per hour, kilometers per hour, meters per second, knots, feet per second and Mach at the same time.
- 62.137 mphmiles per hour
- 53.996 knknots
- 27.778 m/smeters per second
- 91.134 ft/sfeet per second
- 0.08098 MachMach
Speed conversion factors
Read across: 1 unit in the left column equals the value in each other column.
| 1 unit | mph | km/h | m/s | kn | ft/s |
|---|---|---|---|---|---|
| 1 mph | 1 | 1.6093 | 0.44704 | 0.868976 | 1.4667 |
| 1 km/h | 0.621371 | 1 | 0.277778 | 0.539957 | 0.911344 |
| 1 m/s | 2.2369 | 3.6 | 1 | 1.9438 | 3.2808 |
| 1 kn | 1.1508 | 1.852 | 0.514444 | 1 | 1.6878 |
| 1 ft/s | 0.681818 | 1.0973 | 0.3048 | 0.592484 | 1 |
Popular pairs have their own converters with tables: km/h to mph, mph to km/h and knots to mph.
Speed units explained
Miles per hour (mph)
The road speed unit in the United States and the United Kingdom. One statute mile is exactly 1,609.344 meters, so 1 mph is 1.609344 km/h or 0.44704 m/s.
Kilometers per hour (km/h, kph)
The road speed unit in most of the world. “kph” and “kmph” are informal spellings of the same unit. 1 km/h equals 0.621371 mph and exactly 1/3.6 m/s.
Meters per second (m/s)
The SI unit of speed, used in science, engineering and sports analysis. Multiply by 3.6 to get km/h, or by 2.23694 to get mph. A fast walk is about 1.5–2 m/s.
Knots (kn)
One nautical mile (exactly 1,852 m) per hour, used at sea, in aviation and in marine weather. 1 knot = 1.852 km/h = 1.15078 mph.
Feet per second (ft/s)
Common in US engineering, ballistics and driver education. 1 ft/s is 0.3048 m/s; 1 mph is exactly 22/15 ≈ 1.4667 ft/s, so 60 mph is 88 ft/s.
Mach
Speed as a multiple of the speed of sound. Because the speed of sound depends on air temperature, Mach is not a fixed unit. This converter uses 343 m/s — the speed of sound in dry air at 20 °C — so Mach 1 ≈ 1,235 km/h ≈ 767 mph. Aircraft instruments use the local speed of sound instead, which is lower in the cold air at cruising altitude.
Quick conversion tips
- km/h → mph: divide by 1.6 (100 km/h ≈ 62 mph).
- mph → km/h: multiply by 1.6 (50 mph ≈ 80 km/h).
- m/s → km/h: multiply by 3.6 (10 m/s = 36 km/h).
- m/s → mph: roughly double it and add 10% (10 m/s ≈ 22 mph).
- knots → mph: add 15% (20 kn ≈ 23 mph).
- mph → ft/s: add half (60 mph ≈ 90 ft/s; exactly 88).
Want to measure a speed instead of converting it? The GPS speedometer shows your live speed in mph, km/h, knots or m/s.
Frequently asked questions
How do I convert mph to km/h?
Multiply by 1.609344. For example, 60 mph × 1.609344 = 96.56 km/h. Use the mph to km/h converter for a full table.
How do I convert km/h to m/s?
Divide by 3.6. For example, 90 km/h ÷ 3.6 = 25 m/s. To go from m/s to km/h, multiply by 3.6.
How do I convert mph to feet per second?
Multiply by 1.46667 (exactly 22/15). For example, 30 mph is 44 ft/s. This is handy for estimating stopping distances: at 60 mph you travel 88 feet every second.
How fast is Mach 1?
Mach 1 is the speed of sound. It depends on air temperature: in dry air at 20 °C it is about 343 m/s, which is roughly 1,235 km/h or 767 mph. At cruising altitude, where the air is much colder, Mach 1 is closer to 1,060 km/h (660 mph).
Which speed unit is the most precise?
All of them are exact definitions, so none is more precise than another. Scientists use meters per second (the SI unit), road signs use km/h or mph, and ships and aircraft use knots.
Last updated: