Speed converter
Convert any speed via the SI metre per second. Exact international factors, the arithmetic for your input, all equivalents and pace per km / mile.
Defaults to your region. Switch to compare any other scale.
Canonical unit is the metre per second. 1 km/h = 1/3.6 m/s; 1 mph = 0.44704 m/s exact; 1 kn = 1852 m/h exact.
Result
62.137119 mph
km/h → mph
100 km/h × 0.277777777778 = 27.777778 m/s; 27.777778 ÷ 0.44704 = 62.137119 mph
- In SI metres per second27.777778 m/s
- In km/h100 km/h
- Factor (from)1 km/h = 1000/3600 m/s ≈ 0.277778 m/s
- Factor (to)1 mph = 0.44704 m/s
- How calculated100 km/h × 0.277777777778 = 27.777778 m/s; 27.777778 ÷ 0.44704 = 62.137119 mph
- Pace per km0:36 /km
- Pace per mile0:58 /mi
- Cross rate1 km/h = 0.62137119 mph
Via metres per second (SI)
Standards: BIPM SI, international mile 1609.344 m, nautical mile 1852 m. Mach uses ISA sea level (15 °C). 100 km/h × 0.277777777778 = 27.777778 m/s; 27.777778 ÷ 0.44704 = 62.137119 mph
All equivalents
| Unit | Symbol | Value | Factor to m/s |
|---|---|---|---|
| cm/s (centimetres per second) | cm/s | 2,777.778 | 1 cm/s = 0.01 m/s |
| m/s (metres per second) | m/s | 27.777778 | 1 m/s = 1 m/s |
| km/h (kilometres per hour) | km/h | 100 | 1 km/h = 1000/3600 m/s ≈ 0.277778 m/s |
| km/s (kilometres per second) | km/s | 0.02777778 | 1 km/s = 1000 m/s |
| ft/s (feet per second) | ft/s | 91.134442 | 1 ft/s = 0.3048 m/s |
| in/s (inches per second) | in/s | 1,093.613 | 1 in/s = 0.0254 m/s |
| mph (miles per hour) | mph | 62.137119 | 1 mph = 0.44704 m/s |
| kn (knots, nautical miles per hour) | kn | 53.99568 | 1 kn = 1852/3600 m/s ≈ 0.514444 m/s |
| Mach (speed of sound, ISA sea level) | Mach | 0.08162876 | Mach 1 ≈ 340.294 m/s (ISA, sea level, 15 °C) |
| c (speed of light in vacuum) | c | 0.000000092657 | c = 299 792 458 m/s |
About this tool
Speed conversion is a two-step scale change through metres per second: value_ms = value × factor_from; result = value_ms ÷ factor_to.
The factors are exact by definition: 1 km/h = 1000 m ÷ 3600 s = 1/3.6 m/s, so km/h ÷ 3.6 gives m/s. The international mile is exactly 1609.344 m, so 1 mph = 0.44704 m/s and 1 mph = 1.609344 km/h. The nautical mile is exactly 1852 m, so 1 knot = 1.852 km/h. Feet and inches per second use the international foot (0.3048 m) and inch (0.0254 m).
Mach is not a fixed unit: the speed of sound depends on air temperature. This converter uses the ICAO Standard Atmosphere at sea level (15 °C), 340.294 m/s ≈ 1225 km/h. The speed of light c = 299 792 458 m/s is exact. For runners and cyclists the result also shows pace per kilometre and per mile.
Formula
value_ms = value × factor_fromresult = value_ms ÷ factor_to1 km/h = 1/3.6 m/s (exact)1 mph = 0.44704 m/s = 1.609344 km/h (exact)1 kn = 1.852 km/h (exact)pace (min/km) = 1000 ÷ value_ms ÷ 60
How it is calculated
- Enter a speed and pick From / To units.
- Convert to metres per second: value_ms = value × factor_from (e.g. 1 km/h = 1/3.6 m/s).
- Convert to the target: result = value_ms ÷ factor_to.
- Read the step rows for the exact arithmetic of this input, plus pace per km and per mile.
- Open the equivalents table to see km/h, mph, m/s, knots, ft/s and Mach at once.
Questions
How do I convert km/h to mph?
Divide by 1.609344 (the exact number of kilometres in an international mile). Example: 100 km/h ÷ 1.609344 ≈ 62.137 mph. For the reverse, multiply mph by 1.609344.
How do I convert m/s to km/h?
Multiply by 3.6, because one hour has 3600 seconds and one kilometre has 1000 metres. Example: 10 m/s × 3.6 = 36 km/h. From km/h to m/s, divide by 3.6.
What is a knot and how fast is it?
A knot is one nautical mile per hour. The nautical mile is exactly 1852 m, so 1 kn = 1.852 km/h ≈ 1.15078 mph ≈ 0.514444 m/s. Knots are used in aviation, shipping and wind forecasts.
How fast is Mach 1?
Mach 1 is the local speed of sound, which falls as air gets colder. In the ICAO Standard Atmosphere at sea level (15 °C) it is about 340.294 m/s ≈ 1225 km/h ≈ 761 mph. At airliner cruise altitude it is noticeably lower, so treat Mach results here as a sea-level reference.
How do I turn a speed into running pace?
Pace is time per distance, the inverse of speed: minutes per km = 60 ÷ km/h. Example: 12 km/h → 60 ÷ 12 = 5:00 per km, or about 8:03 per mile. The result rows show both automatically.
Are the results official metrology advice?
No. Calculate This is educational. For legal metrology, speed enforcement or aviation, use your national authority's guidance and calibrated instruments.