25 mph = 21.7244 kn (mile per hour → knot)
25 mph = 21.7244 kn
25 miles per hour (mph) equals 21.7244 knots (kn). The conversion uses the exact factor 0.868976: 25 × 0.868976 = 21.7244.
Knots = Miles per hour × 0.868976How 25 miles per hour compares to its arithmetic neighbours, converted to knots.
| Relation | miles per hour | knots |
|---|---|---|
| ÷10 | 2.5 mph | 2.17244 kn |
| ÷2 (half) | 12.5 mph | 10.8622 kn |
| ×1 (this value) | 25 mph | 21.7244 kn |
| ×2 (double) | 50 mph | 43.4488 kn |
| ×5 | 125 mph | 108.622 kn |
| ×10 | 250 mph | 217.244 kn |
Miles per hour to knots divides by 1.15078. A 60 mph boat does 52.14 knots; a 150 mph small plane is 130 knots. Convert to knots when reading nautical charts or filing flight plans, where distances are in nautical miles and speed in knots keeps the arithmetic clean (distance ÷ speed gives time in hours directly). For everyday land travel mph stays standard; knots are a navigation-domain unit.
General-aviation flight schools convert this constantly when training pilots to read an airspeed indicator: a Cessna's 120 mph never-exceed speed marked on an older US instrument corresponds to 104.3 knots on the international aviation charts a student also has to read, since flight planning and air-traffic control communicate exclusively in knots regardless of what a specific cockpit gauge is calibrated in.
Start with your value in miles per hour.
Multiply the mile per hour value by 0.868976. This is the exact conversion factor from miles per hour to knots.
The product is your value in knots. For example, 5 mph × 0.868976 = 4.34488 kn.
The exact factor from miles per hour to knots is 0.868976.
Knots = Miles per hour × 0.868976
Fifty common reference values, hand-picked for skim utility. Use the calculator above for any value not listed.
| Miles per hour (mph) | Knots (kn) |
|---|---|
| 1 mph | 0.86898 kn |
| 2 mph | 1.738 kn |
| 3 mph | 2.6069 kn |
| 4 mph | 3.4759 kn |
| 5 mph | 4.3449 kn |
| 6 mph | 5.2139 kn |
| 7 mph | 6.0828 kn |
| 8 mph | 6.9518 kn |
| 9 mph | 7.8208 kn |
| 10 mph | 8.6898 kn |
| 12 mph | 10.428 kn |
| 15 mph | 13.035 kn |
| 18 mph | 15.642 kn |
| 20 mph | 17.38 kn |
| 22 mph | 19.117 kn |
| 25 mph | 21.724 kn |
| 28 mph | 24.331 kn |
| 30 mph | 26.069 kn |
| 32 mph | 27.807 kn |
| 35 mph | 30.414 kn |
| 40 mph | 34.759 kn |
| 45 mph | 39.104 kn |
| 50 mph | 43.449 kn |
| 55 mph | 47.794 kn |
| 60 mph | 52.139 kn |
| 65 mph | 56.483 kn |
| 70 mph | 60.828 kn |
| 75 mph | 65.173 kn |
| 80 mph | 69.518 kn |
| 85 mph | 73.863 kn |
| 90 mph | 78.208 kn |
| 95 mph | 82.553 kn |
| 100 mph | 86.898 kn |
| 110 mph | 95.587 kn |
| 120 mph | 104.28 kn |
| 130 mph | 112.97 kn |
| 140 mph | 121.66 kn |
| 150 mph | 130.35 kn |
| 160 mph | 139.04 kn |
| 180 mph | 156.42 kn |
| 200 mph | 173.8 kn |
| 220 mph | 191.17 kn |
| 250 mph | 217.24 kn |
| 280 mph | 243.31 kn |
| 300 mph | 260.69 kn |
| 350 mph | 304.14 kn |
| 400 mph | 347.59 kn |
| 500 mph | 434.49 kn |
| 700 mph | 608.28 kn |
| 1000 mph | 868.98 kn |
US Interstate speed limits are usually 65–75 mph. A 4-minute mile is exactly 15 mph. In knots, that gives you: 1 mph = 0.868976 kn, 10 mph = 8.68976 kn, 100 mph = 86.8976 kn.
The mile per hour (mph) is the customary speed unit in the United States and the United Kingdom. The conversion 1 mph = 0.44704 m/s is exact, derived from 1 mile = 1609.344 m. A useful mental shortcut: multiply mph by 1.6 to get a close km/h estimate.
The knot (kn) is one nautical mile per hour, or exactly 1852/3600 ≈ 0.5144 m/s. It is the standard speed unit in maritime and aviation use because it relates directly to latitude — one knot covers one minute of arc per hour. The name comes from the historical practice of measuring ship speed by counting knots passed on a line trailing behind the vessel.
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