1 mile per hour = 0.86897624 kn
1 mph = 0.868976 kn · type math like (12*4)+6.5
Mph to knots helps boaters and pilots translate road-style speeds or US weather reports into the units used on charts and in cockpits.
US hurricane advisories from the National Hurricane Center list wind speeds in both mph and knots. A Category 4 hurricane at 130 mph is 113 kn, and forecasters work internally in knots, rounding to the nearest 5 kn.
Boat owners who have a car-style GPS app reading mph need to convert to knots for nautical charts and logs. A boat at 25 mph is doing 21.7 kn, and a no-wake zone limit of 5 mph is about 4.3 kn.
Drone and small aircraft pilots may see specifications in mph but receive wind reports in knots. A drone with a maximum wind resistance of 24 mph can handle about 20.9 kn.
In aviation, true airspeed, ground speed and indicated airspeed are all quoted in knots. Converting a road-style mph figure is just the start of flight planning.
Weather balloon and aviation charts express winds aloft in knots. US television forecasts, however, use mph. A jet stream core of 200 mph is 173.8 kn, and pilots plan around these winds to save fuel on eastbound flights.
Sailing races are scored and reported in knots. When a news story mentions a racing yacht hitting 50 mph, sailors will convert that to 43.4 kn to compare with records.
Seaplanes and amphibious aircraft are a special case where both units matter. Their takeoff speeds on water are given in knots, but road towing and trailer limits are in mph. A towing speed limit of 55 mph is 47.8 kn.
Racing yachts in the America's Cup now foil above the water at speeds above 50 kn, which is 57.5 mph. Media in the US often report these speeds in mph, while race officials use knots.
Kitesurfers and windsurfers check wind in knots. A forecast of 20 mph in a US app is 17.4 kn, a good wind for most kite sizes.
To check an answer, the knot figure should be about 13% smaller than the mph figure. 80 mph should come out near 70 knots (69.5 exactly). If your answer is larger than the mph figure, you multiplied by 1.15 instead of dividing. Pilots and sailors usually round knots to the nearest whole number, because instruments and charts rarely show decimals.
kn = mph × 0.8689762419
Reverse: 1 kn = 1.1507794 mph.
Convert 150 mph to knots.
Answer: 150 mph = 130.3 kn.
| mph | kn |
|---|---|
| 1 mph | 0.86897624 kn |
| 2 mph | 1.7379525 kn |
| 3 mph | 2.6069287 kn |
| 4 mph | 3.475905 kn |
| 5 mph | 4.3448812 kn |
| 6 mph | 5.2138575 kn |
| 7 mph | 6.0828337 kn |
| 8 mph | 6.9518099 kn |
| 9 mph | 7.8207862 kn |
| 10 mph | 8.6897624 kn |
| 11 mph | 9.5587387 kn |
| 12 mph | 10.427715 kn |
| 13 mph | 11.296691 kn |
| 14 mph | 12.165667 kn |
| 15 mph | 13.034644 kn |
| mph | kn |
|---|---|
| 16 mph | 13.90362 kn |
| 17 mph | 14.772596 kn |
| 18 mph | 15.641572 kn |
| 19 mph | 16.510549 kn |
| 20 mph | 17.379525 kn |
| 25 mph | 21.724406 kn |
| 30 mph | 26.069287 kn |
| 40 mph | 34.75905 kn |
| 50 mph | 43.448812 kn |
| 75 mph | 65.173218 kn |
| 100 mph | 86.897624 kn |
| 250 mph | 217.24406 kn |
| 500 mph | 434.48812 kn |
| 1 000 mph | 868.97624 kn |
A Cessna 172 cruising at 140 mph is doing 121.7 kn.
25 mph wind is 21.7 kn, Beaufort force 6.
150 mph winds aloft are 130.3 kn.
That goes from knots to mph. Divide mph by 1.151.
Unit conversion does not correct for altitude. Convert first, then apply flight corrections.
0.9 overstates. 150 mph becomes 135 kn instead of 130.3.
1 mph = 0.868976 knots.
Origin. British statute mile per hour.
Used today. Roads and public weather in the US.
1 knot = 1 nautical mile (1,852 m) per hour.
Origin. From knotted log lines used on ships since the 1600s.
Used today. Navigation at sea and in the air.
52.1 kn.
0.869 kn.
Because one nautical mile equals one minute of latitude, making navigation on charts simple.
Subtract 13%: 100 mph → 87 kn (exact 86.9).
Usually, though it is often shown in mph and km/h too.