Speed Converter
Convert km/h, mph, m/s, knots and feet per second.
Convert km/h, mph, m/s, knots and feet per second in real time — handy for driving abroad, running stats, sailing and physics.
Formula / method
Examples
62.137 mph
96.561 km/h
How the speed units relate
Speed conversions are exact ratios. One metre per second equals 3.6 km/h, one mile per hour equals about 1.609 km/h, one knot equals exactly 1.852 km/h, and one foot per second equals 0.3048 m/s. The converter applies these factors so you can move between any two units instantly.
Knots and nautical miles are used in aviation and shipping because a nautical mile matches one minute of latitude, which makes navigation charts simpler.
Where each unit is used
Different regions and fields favour different units: km/h on most road signs, mph in the US and UK, m/s in physics problems, knots at sea and in the air, and feet per second in ballistics. Knowing the context helps you pick the right target unit.
A frequent mistake is confusing speed with pace. Runners often think in minutes per kilometre rather than distance per hour; for that, use the Running Pace Calculator instead.
Where it's used
- Converting a speed limit from km/h to mph when driving abroad
- Reading aircraft or boat speed in knots against km/h or mph
- Turning m/s into km/h for physics homework and lab reports
- Comparing wind speeds reported in different units across weather forecasts
- Checking treadmill or cycling speeds between metric and imperial
Real-world examples
- A 100 km/h motorway limit in Europe converts to about 62 mph for a visiting US driver.
- A ship cruising at 20 knots is moving at about 37 km/h.
- A physics problem giving 25 m/s shows as exactly 90 km/h.
A bit of history
The knot as a unit of speed comes from the chip log: a rope knotted at fixed intervals was let out behind a moving ship while a sandglass timed it, and the number of knots that ran out gave the speed. The device was described in print by William Bourne in 1574.
Did you know?
A knot is one nautical mile per hour, and a nautical mile was originally defined as one minute of latitude, so a vessel steaming due north at 60 knots covers a full degree of latitude in an hour.
FAQ
What is a knot?
A knot is one nautical mile per hour, equal to about 1.852 km/h. It is used in maritime and aviation contexts.