Speed Converter

Converts speed across m/s, km/h, mph, knots and ft/s. One m/s is 3.6 km/h; one mph is 1.609 km/h; one knot — a nautical mile per hour — is 1.852 km/h. Type in any unit and the rest follow.

How to use

1. Enter the speed in the unit you have.
2. Read the equivalents in the others.
3. For pace-style figures (minutes per km), convert the distance-over-time first — this tool works in distance per time.
4. Wind speeds arrive in every unit depending on source; convert before comparing.

When you actually need this

• Reading a US speed limit or car spec in km/h — 60 mph is 96.6 km/h.
• Converting wind speed between weather sources that use knots, m/s or km/h.
• Translating physics-class m/s into road intuition — 30 m/s is 108 km/h.
• Comparing running-machine mph settings against km/h habits.

Where the knot comes from

The knot is one nautical mile (1,852 m) per hour, and the nautical mile is one minute of latitude — which is why ships and aircraft, navigating on the globe's geometry, still use it. The name is literal: sailors counted knots in a rope paid out behind the ship against a sandglass. The m/s–km/h factor of 3.6 is exact and worth memorising for physics; the mph factor inherits the exact 1,609.344 m mile. Weather services habitually mix units — Korean forecasts in m/s, aviation in knots, US media in mph — so the same storm can sound three different strengths until you convert.

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FAQ

How precise are the conversion factors in Speed Converter?

The factors are the internationally defined exact values — one inch is exactly 25.4 millimetres, one pound is exactly 0.45359237 kilograms, and so on. Results are computed at full floating-point precision and only rounded for display.

Can I convert between metric and imperial units in both directions?

Yes. Enter a value in any field and every other unit updates at once, so the conversion works in either direction without switching modes or pressing a button.

Why does the last decimal place sometimes look off?

Because many conversions are irrational in decimal form and browsers use binary floating point, the final digit can differ by a tiny amount. The displayed value is rounded sensibly for everyday use; for laboratory or engineering work, carry the unrounded figure through your own calculation.