Speed Converter Online

Speed gets measured differently depending on context — kilometres per hour for road traffic, miles per hour in the US and UK, knots for maritime and aviation, metres per second in physics. This tool converts any speed value across all common units instantly.

How it works

Enter a value, pick your source unit, and the tool calculates the equivalent in all other units using standard conversion constants. Everything runs client-side in your browser.

How to use it

1. Enter your numeric speed value
2. Select the source unit from the dropdown
3. Read the converted results — click any to copy it

Supported units

Metres per second (m/s), kilometres per hour (km/h), miles per hour (mph), knots, feet per second (ft/s), and Mach number (at sea level).

A few things worth knowing

• Knots: One knot = one nautical mile per hour = 1.852 km/h. Used in aviation and maritime navigation
• Mach number: The ratio of an object's speed to the speed of sound. Mach 1 ≈ 343 m/s at sea level at 20°C — it changes with altitude and temperature, so the conversion here uses the sea-level standard
• m/s to km/h: Multiply by 3.6. That's the most common quick conversion in physics problems

FAQ

How fast is 100 km/h in mph? About 62.1 mph. Multiply km/h by 0.621371 to convert.

What is Mach 1 in km/h? At sea level (standard conditions), Mach 1 ≈ 1,235 km/h or 767 mph.

What's a knot in km/h? 1 knot = 1.852 km/h exactly (by definition).

Related Tools

• Unit Converter
• Length Converter