Speed Converter
Convert between 13 speed units instantly. Enter a value, pick your units and get the result with the formula, a full conversion table and worked examples.
100 km/h in all speed units
Updates live as you type. Click a row to set it as the target unit.
| Unit | Symbol | Value |
|---|---|---|
| Millimetre per second | mm/s | 27,777.8 |
| Centimetre per second | cm/s | 2,777.78 |
| Metre per minute | m/min | 1,666.67 |
| Metre per second | m/s | 27.7778 |
| Kilometre per hour | km/h | 100 |
| Kilometre per second | km/s | 0.0277778 |
| Inch per second | in/s | 1,093.61 |
| Foot per minute | ft/min | 5,468.07 |
| Foot per second | ft/s | 91.1344 |
| Mile per hour | mph | 62.1371 |
| Knot | kn | 53.9957 |
| Mach (sea level) | Ma | 0.0816297 |
| Speed of light | c | 9.26567 × 10−8 |
How to Convert Speed Units
Speed is the distance travelled per unit time. The SI unit is metre per second (m/s); road speeds use km/h or mph, ships and aircraft use knots, and Mach here is referenced to sea level standard air (340.29 m/s).
Every unit on this page is stored as a fixed factor relative to one reference unit, the metre per second (m/s). Converting is a two step multiply and divide:
- Multiply your value by the factor of the source unit to get the value in m/s.
- Divide that result by the factor of the target unit.
Kilometre per hour to Mile per hour conversion table
| Kilometre per hour (km/h) | Mile per hour (mph) |
|---|---|
| 1 km/h | 0.621371 mph |
| 2 km/h | 1.24274 mph |
| 3 km/h | 1.86411 mph |
| 4 km/h | 2.48548 mph |
| 5 km/h | 3.10686 mph |
| 6 km/h | 3.72823 mph |
| 7 km/h | 4.3496 mph |
| 8 km/h | 4.97097 mph |
| 9 km/h | 5.59234 mph |
| 10 km/h | 6.21371 mph |
| 15 km/h | 9.32057 mph |
| 20 km/h | 12.4274 mph |
| 25 km/h | 15.5343 mph |
| 30 km/h | 18.6411 mph |
| 40 km/h | 24.8548 mph |
| 50 km/h | 31.0686 mph |
| 75 km/h | 46.6028 mph |
| 100 km/h | 62.1371 mph |
| 250 km/h | 155.343 mph |
| 500 km/h | 310.686 mph |
| 1,000 km/h | 621.371 mph |
Speed Units and Conversion Factors
Value of one unit expressed in m/s.
| Unit | Symbol | In m/s |
|---|---|---|
| Millimetre per second | mm/s | 0.001 |
| Centimetre per second | cm/s | 0.01 |
| Metre per minute | m/min | 0.01666666667 |
| Metre per second | m/s | 1 |
| Kilometre per hour | km/h | 0.2777777778 |
| Kilometre per second | km/s | 1,000 |
| Inch per second | in/s | 0.0254 |
| Foot per minute | ft/min | 0.00508 |
| Foot per second | ft/s | 0.3048 |
| Mile per hour | mph | 0.44704 |
| Knot | kn | 0.5144444444 |
| Mach (sea level) | Ma | 340.29 |
| Speed of light | c | 299,792,458 |
Frequently Asked Questions
What is the SI unit of speed?
The SI unit of speed is the metre per second (m/s). Speed is the distance travelled per unit time.
How do I convert km/h to mph?
To convert kilometre per hour (km/h) to mile per hour (mph), multiply the value in km/h by 0.621371. For example, 1 km/h = 0.621371 mph.
How do I convert mph to km/h?
To convert mile per hour (mph) to kilometre per hour (km/h), multiply the value in mph by 1.60934. For example, 1 mph = 1.60934 km/h.
How do I convert m/s to km/h?
To convert metre per second (m/s) to kilometre per hour (km/h), multiply the value in m/s by 3.6. For example, 1 m/s = 3.6 km/h.
Can I see a value in every speed unit at once?
Yes. Enter a value and choose the source unit; the "all units" table below the converter instantly lists the equivalent in all 13 supported units. Click any row to make it the target unit.
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