Speed Converter - Online Mini Tools

Convert any speed value between common metric and imperial units, plus specialty units such as knots, Mach (ISA / sea level), and the speed of light. The converter runs entirely in your browser and updates instantly as you type.

Supported speed units

Metric: centimeters/second, meters/second (m/s), meters/minute, meters/hour, kilometers/hour (km/h), kilometers/second (km/s).
Imperial: inches/second, inches/minute, feet/second, feet/minute, feet/hour, yards/second, yards/minute, yards/hour, miles/hour (mph), miles/minute, miles/second.
Nautical: knots, nautical miles/hour, Nm/24hr (Volvo Ocean Race pace metric).
Aviation & physics: Mach number at the International Standard Atmosphere sea level (≈ 340.29 m/s) and the speed of light in vacuum (299,792,458 m/s).

Conversion approach

Every supported unit has a known factor for converting to meters per second. The tool first converts your input to m/s using the source factor, then divides by the destination factor. This yields accurate results without compounding floating-point rounding from intermediate units.

Tips

Use the Swap button to flip the source and target units without retyping the value.
Mach values vary with altitude and temperature — the conversion here assumes standard sea-level conditions.
For relativistic speeds, the result is reported as a fraction of c when the target unit is "speed of light".

Frequently Asked Questions

How accurate is the Mach conversion?

The tool uses 340.29 m/s as the sea-level ISA speed of sound. Real Mach numbers depend on air temperature and altitude, so atmospheric corrections are required for in-flight calculations.

What is a knot?

One knot equals one nautical mile per hour, which is exactly 1.852 km/h or about 1.15078 mph. Knots are the standard speed unit in marine and aviation contexts.

Does the converter handle very large speeds like the speed of light?

Yes. The speed of light (c) is treated as 299,792,458 m/s, allowing you to express speeds as a fraction of c or convert sub-light speeds into a fraction of c.

What is Nm/24hr (Volvo Ocean Race)?

It is the average sailing speed expressed as nautical miles covered in 24 hours — a popular reporting unit in ocean racing. It equals the value in knots divided by 24.

Is the input saved or uploaded?

No. All computation happens locally in your browser, so values you type never leave your device.