km/h, mph, Knots: How to Convert Speed Online

Speed is measured differently depending on the country and field: km/h is standard in most countries, mph in the US and UK, knots in aviation and shipping, m/s in physics and sports. Reading foreign specs or sports data often calls for converting one unit into another.

What the converter converts

The speed converter converts values between meters per second (m/s), kilometers per hour (km/h), miles per hour (mph), knots (kn), and feet per second. Enter a number into any field, and the other units update instantly.

Where this matters

• Cars — specs for vehicles from the US and UK (acceleration, top speed, road sign limits) are listed in mph. For example, the familiar 60 mph limit is roughly 97 km/h.
• Aviation and shipping — aircraft and vessel speed is traditionally measured in knots (nautical miles per hour).
• Sports and physics — running, throwing, or motion speed in scientific calculations is more often expressed in meters per second.

Reference values for a quick estimate

• 1 km/h ≈ 0.278 m/s
• 1 mile per hour (mph) ≈ 1.609 km/h
• 1 knot ≈ 1.852 km/h

To quickly convert km/h to m/s in your head, just divide by 3.6 — and multiply by 3.6 to go the other way, from m/s to km/h.

How the calculation works

The conversion uses meters per second as the reference unit: the entered value is first converted to m/s, then into the target unit. This guarantees an accurate result for any pair of units.

Bottom line

A speed converter removes the need to manually convert between km/h, m/s, mph, knots, and feet per second — useful when reading foreign vehicle specs, and in aviation, shipping, and sports. The calculation happens instantly right in the browser.