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العربيةSpeed converter — km/h, mph, m/s and knots
Road signs in mph, physics homework in m/s, weather reports in knots, the odd aircraft figure in Mach. Six speed units, recalculated on every keystroke.
How to use it
- 1
Type into any row — say km/h or mph. The results appear immediately, no button needed.
- 2
Need a combined figure? Fill in two rows, for example km/h and m/s, and they are added together before converting.
- 3
Set how many digits you want (4–12) and click a result to copy the plain number.
Exact conversion factors
These are the definitions the calculator uses. Nothing here is rounded for convenience — where a value is exact by definition, it says so.
- 1 m/s = 3.6 km/h exactly = 2.23693629 mph
- 1 mph = 1.609344 km/h exactly = 0.44704 m/s
- 1 knot = 1.852 km/h = 0.514444444 m/s
- 100 km/h = 62.1371192 mph · 60 mph = 96.56064 km/h
- Mach 1 at 15 °C, sea level = 340.29 m/s = 1225 km/h
km/h = m/s × 3.6 · km/h = mph × 1.609344 · km/h = kn × 1.852Speed conversion table — every unit
One of each unit, converted into the three units people ask for most.
| Unit | km/h | mph | m/s |
|---|---|---|---|
| 1 km/h | 1 km/h | 0.621371 mph | 0.277778 m/s |
| 1 m/s | 3.6 km/h | 2.23694 mph | 1 m/s |
| 1 mph | 1.60934 km/h | 1 mph | 0.44704 m/s |
| 1 ft/s | 1.09728 km/h | 0.681818 mph | 0.3048 m/s |
| 1 kn | 1.852 km/h | 1.15078 mph | 0.514444 m/s |
| 1 Mach | 1 225.04 km/h | 761.207 mph | 340.29 m/s |
km/h → mph, m/s — quick values
| km/h | mph | m/s |
|---|---|---|
| 0.5 km/h | 0.310686 mph | 0.138889 m/s |
| 1 km/h | 0.621371 mph | 0.277778 m/s |
| 2 km/h | 1.24274 mph | 0.555556 m/s |
| 3 km/h | 1.86411 mph | 0.833333 m/s |
| 5 km/h | 3.10686 mph | 1.38889 m/s |
| 10 km/h | 6.21371 mph | 2.77778 m/s |
| 20 km/h | 12.4274 mph | 5.55556 m/s |
| 25 km/h | 15.5343 mph | 6.94444 m/s |
| 50 km/h | 31.0686 mph | 13.8889 m/s |
| 100 km/h | 62.1371 mph | 27.7778 m/s |
| 250 km/h | 155.343 mph | 69.4444 m/s |
| 1 000 km/h | 621.371 mph | 277.778 m/s |
How this converter works
The conversions people reach for most: 100 km/h is 62.14 mph, 60 mph is 96.56 km/h, and 1 m/s is 3.6 km/h exactly. The last one is worth memorising, since it turns most physics answers into everyday numbers in one step.
Knots come from sea navigation — one nautical mile per hour, or 1.852 km/h — and are still standard in aviation and marine forecasts. Mach is included as a reference at 340.29 m/s, the speed of sound in dry air at 15 °C at sea level; it drops with temperature, so treat it as an approximation rather than a fixed conversion.
Notes and abbreviations
- kn — knot, one nautical mile per hour, 1.852 km/h
- 1 m/s = 3.6 km/h exactly; 1 mph = 1.609344 km/h exactly
- Mach 1 varies with air temperature — the value here is the sea-level standard
Questions
What is 100 km/h in mph?
62.1371 mph. Going the other way, 70 mph is 112.654 km/h.
How do I convert m/s to km/h in my head?
Multiply by 3.6. A 10 m/s wind is a 36 km/h wind.
Why is Mach not a fixed speed?
It is a ratio to the local speed of sound, which falls as air gets colder. At cruising altitude Mach 1 is roughly 295 m/s, not 340.