Knots to Kilometers per hour

About Knots and Kilometers per hour

Knots (kn): One nautical mile per hour; a nautical mile is 1,852 m, based on one minute of arc along a meridian (so the unit is tied to Earth's geometry). Common uses: Marine navigation (ship speeds), aviation (aircraft speeds), and meteorology (wind speeds in weather reports for sailing and flying).

Kilometers per hour (km/h): A practical unit derived from the kilometer (defined via the meter) and the hour (60 × 60 seconds). Common uses: Vehicle speed limits worldwide except in the US and a few other countries, train and aircraft cruise speeds (in metric contexts), and weather wind speeds.

How the conversion works

Speed is distance per unit time. 1 m/s = 3.6 km/h. 1 mph = 1.609344 km/h. 1 knot = 1.852 km/h (one nautical mile per hour).

The exact relationship is kilometers per hour = knots × 1.85199692e+0, which the calculator at the top of this page applies in both directions. Type into either field and the other updates immediately.

When this conversion matters

Converting between knots and kilometers per hour comes up wherever speed measurements move between systems — from one country's conventions to another's, from a scientific reference to a practical specification, or from one industry's working unit to another's. The calculator and reference table above cover the everyday range; for unusual values you can type any number into either field.