Knots to Miles per Hour

Knots and miles per hour

The knot is one nautical mile per hour: exactly 1.852 km/h. Ships, aircraft, and wind speeds in aviation and marine forecasts are measured in knots.

A mile per hour is one international mile per hour: exactly 0.44704 m/s, or 1.609344 km/h. Speed limits and speedometers in the US and UK, and pitch speeds in baseball, use mph.

Worked example

Convert 20 kn: 20 × 1.150779448 = 23.01558896, so 20 knots is 23.01558896 miles per hour. Likewise 50 kn = 57.5389724 mph.

Estimating in your head

Multiply by 1.2 for a quick figure; it is off by about 4.3%. For 20 kn that gives 24 mph, against 23.0156 exactly.

Going the other way

To convert miles per hour to knots, divide by 1.150779448 (or multiply by 0.868976241901). The swap button between the boxes opens that page.

mph = kn × 1.150779448

1 kn = ≈ 0.5144444444 m/s and 1 mph = 0.44704 m/s, both by definition, so the factor is their ratio: 1.150779448 (rounded here; the page uses the full value). Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.