Velocity Calculator
Convert speed between km/h, mph, m/s, knots, feet per second, Mach and the speed of light. Type a speed in any unit and see all equivalents at once. Covers per-second, per-minute and per-hour variants of meters, kilometers, miles and feet, which is useful for driving, running, aviation and physics.
What does the Velocity Calculator do?
It converts a speed into 15 units at once: meters, kilometers, miles and feet per second, per minute and per hour, plus knots, Mach and the speed of light (c). Enter a value in any row; the others are recalculated in your browser using exact factors such as 1 mi = 1,609.344 m and 1 kn = 1,852 m/h.
How to use
- Enter a speed in the row of its unit, for example 100 in Kilometer per Hour. You get ≈ 62.1371 mph and ≈ 27.7778 m/s.
- Adjust rounding digits to show more or fewer decimal places.
- Check Ratio to show each unit relative to the top row, Separators for thousands separators, or Description for definitions.
- Drag a row by its handle to reorder; the first row is used as the (base unit).
- Press Up / Down in a field to increase or decrease the speed by 1 of that unit.
Units
| Unit | Symbol | Definition |
|---|---|---|
| Meter per second | m/s | SI unit of speed |
| Kilometer per hour | km/h | 1/3.6 m/s |
| Meter / kilometer per minute | m/min, km/min | 1/60 m/s, 1,000/60 m/s |
| Mile per hour | mph | 1,609.344 m per hour ≈ 0.44704 m/s |
| Foot per second | ft/s | 0.3048 m/s |
| Knot | kn | 1 nautical mile (1,852 m) per hour |
| Mach | mach | Fixed at 343 m/s |
| Speed of light | c | 299,792,458 m/s (exact) |
Per-second, per-minute and per-hour versions are available for meters, kilometers, miles and feet (m/h, mi/s, mi/min, ft/min, ft/h, and so on).
Conversion examples
- 1 m/s = 3.6 km/h
- 60 mph ≈ 96.5606 km/h
- 1 kn = 1.852 km/h ≈ 1.15078 mph
- Mach 1 = 343 m/s = 1,234.8 km/h
- c = 1,079,252,848.8 km/h
Features
- 15 speed units in one reorderable list
- Bidirectional: edit any row
- Decimal arithmetic with 40 significant digits
- Optional ratios, thousands separators and unit descriptions
- Remembers your unit order, value and options in this browser
FAQ
Why is Mach fixed at 343 m/s?
The speed of sound depends on air temperature and altitude. This tool uses 343 m/s, the speed of sound in dry air at 20 °C, so a Mach value here is an approximation rather than the Mach number an aircraft instrument would show.
Can I calculate speed from distance and time, or pace (min/km)?
No. The tool converts a speed between units. Divide distance by time first, then enter the result. Pace units such as minutes per kilometer are not included.
Is anything sent to a server?
No. Calculations happen in your browser.