TontonTools

Speed Converter

Convert km/h, mph, m/s, knots and ft/s for driving, running and flying.

100% Free No signup Privacy-friendly Unit Converters
Updated Sep 2026

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How to use Speed Converter

  1. Enter the speed in the “From” field — for example 120 for 120 km/h.
  2. Select the unit it is in (Km/hour, Mile/hour, Knot…) from the first dropdown.
  3. Select the unit you want from the second dropdown — the converted speed appears instantly.
  4. Click the swap button to reverse the conversion, e.g. mph → km/h becomes km/h → mph.

What is Speed Converter?

A speed converter translates velocity between units — kilometers per hour to miles per hour, meters per second to km/h, or knots to mph. Which unit you meet depends on context: road signs use km/h in most of the world and mph in the US and UK; physics and weather models use meters per second; aviation and sailing use knots.

The relationships are exact: 1 mph = 1.609344 km/h (from the mile), 1 knot = 1.852 km/h (one nautical mile per hour), and 1 m/s = 3.6 km/h exactly — a clean factor that makes m/s the easiest unit to convert in your head.

About the Speed Converter

This converter covers five units — meters per second, kilometers per hour, miles per hour, feet per second and knots — converting between any pair the instant you type.

Real uses: a US car doing 65 mph is at 105 km/h — useful when renting a car abroad; a hurricane reported at 100 knots is blowing 185 km/h (115 mph); a sprinter running 100 m in 10 s averages 10 m/s = 36 km/h; a wind forecast of 15 m/s is a stiff 54 km/h. Anchors: 100 km/h ≈ 62 mph, 1 knot ≈ 1.15 mph, and to turn m/s into km/h just multiply by 3.6.

Everything is computed locally with exact factors — nothing typed here leaves your browser.

Frequently Asked Questions

Multiply by 0.6214 (or divide by 1.609). So 100 km/h = 62.1 mph and 130 km/h — a common European motorway limit — is 80.8 mph.
One knot is one nautical mile per hour = 1.852 km/h = 1.1508 mph. Ships and aircraft use knots because nautical miles align with latitude minutes on navigation charts.
Because an hour has 3,600 seconds and a kilometer 1,000 meters, 1 m/s is exactly 3.6 km/h. Multiply m/s by 3.6 — a 10 m/s wind is 36 km/h.
About 343 m/s at sea level and 20 °C — that is 1,235 km/h or 767 mph. It varies with air temperature, which is why Mach number is not a fixed speed.
A 5-minute-per-km pace equals 12 km/h, 7.46 mph or 3.33 m/s. Marathon world-record pace is around 21 km/h (13 mph) — sprint speed for most people.

Learn more

How to Convert km/h to mph and Other Speed Units

Driving abroad or reading specs in different units? Here is how to convert between km/h, mph, m/s and knots.

Read the guide

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