Convert Mile per Hour to Knot (mph → kn)

Converting miles per hour to knots is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in miles per hour

   Start with the number of miles per hour (mph) you want to convert.
2. 2
   Multiply by 0.868976

   The conversion factor from mph to kn is 0.868976. Multiply your value by this number.
3. 3
   Read the result in knots

   The result is your value in knots (kn).

Multiply the value in miles per hour by 0.868976. For the reverse direction, multiply by 1.150779.

• ✓1 mph = 1.609 km/h = 0.447 m/s.
• ✓Quick convert: mph × 1.6 = km/h.
• ✓UK speeds posted in mph on road signs despite general metrication.

• ✗Reading a UK road sign "50" as km/h — it's mph (= 80 km/h).
• ✗Converting mph to km/h by multiplying by 1.5 instead of 1.609 — 7% error.
• ✗Assuming "mph" and "MPH" differ — capitalisation does not matter.

What is the Mile per Hour?

Miles per hour is the road-speed standard in the United States, the United Kingdom, and several Caribbean countries. American and British road signs, car speedometers, and weather reports use mph. Typical US speed limits are 25 mph (residential), 35–45 mph (urban arterials), 55–65 mph (rural highways), and 65–80 mph (interstates). The UK uses mph despite metric measurement elsewhere — a result of incomplete metrication. Mph derives from the mile (distance) and hour (time): 1 mph ≈ 1.609 km/h ≈ 0.447 m/s. World-class sprinters reach about 27 mph, professional baseball pitchers throw at 90–105 mph, and commercial airliners cruise at 550–600 mph. The unit relates to km/h (1 mph ≈ 1.609 km/h), m/s (1 mph ≈ 0.447 m/s), the knot (1 mph ≈ 0.869 kn), and ft/s (1 mph ≈ 1.467 fps).

• US and UK road speed limits
• US car speedometers
• US baseball pitch speeds

What is the Knot?

The knot equals exactly one nautical mile per hour (1.852 km/h or 0.5144 m/s) and is the universal speed unit for ships and aircraft worldwide. The name derives from the historical practice of measuring ship speed by counting knots tied at regular intervals along a 'log line' that was let out over the stern of a ship — the number of knots that passed in a given time gave the speed. International maritime regulations, aviation flight plans, and weather reports for sailors all use knots. A typical cruise ship sails at 18–22 knots, container ships at 18–25 knots, and commercial airliners at 470–500 knots cruise speed. The knot relates to km/h (1 knot ≈ 1.852 km/h), mph (1 knot ≈ 1.151 mph), m/s (1 knot ≈ 0.514 m/s), and the nautical mile (1 knot = 1 nmi/h). Wind speeds in aviation are also given in knots.

• Ship speeds and ocean currents
• Aircraft airspeed and ground speed
• Marine weather (wind reports in knots)