Convert mph to knots

One mile per hour equals 0.868976 knots. To convert any number of miles per hour to knots, multiply by 0.86897624.

The converter above works in both directions and updates as you type. Below you will find the formula, a worked example and a reference table of common values.

Speed conversions divide by audience. Road speeds move between kilometres and miles per hour and are what a driver or a runner needs. Metres per second is what every equation of motion expects, so it is the form any physics problem has to reach. Knots belong to the sea and the air, where one knot is one nautical mile per hour and a nautical mile is one minute of latitude — a system built around navigation rather than around convenience.

mph to knots formula

To go the other way, use mile per hour = knot ÷ 0.86897624.

About these units

Miles per hour remains the road-speed unit in the United States and the United Kingdom, which is why British road signs are in miles while everything else on them is metric.

One knot is one nautical mile per hour. The name comes from the knotted rope once trailed behind a ship to measure its speed.

Mile per hour is also written miles per hour and mi/h. Knot is also written knots, kts, kt, nautical miles per hour, knoten, nudos and noeuds.

Sources

1. National Bureau of Standards, "Refinement of Values for the Yard and the Pound", Federal Register, 1 July 1959 — the international yard as exactly 0.9144 m and the avoirdupois pound as exactly 0.45359237 kg.
2. International Hydrographic Conference, Monaco, 1929 — the international nautical mile as exactly 1,852 metres, from which the knot follows.