Miles per Hour to Knots (mph to kn) Converter
1 mile per hour equals 0.86897624 knots — multiply the number of miles per hour by 0.86897624 to convert to knots. A knot is one nautical mile per hour (1.852 km/h), which is faster than a statute mile per hour, so mph values become slightly smaller in knots. The factor is exact.
The formula
To convert miles per hour to knots, multiply by the exact factor:
knots = mph × 0.86897624
For example, 50 mph × 0.86897624 = 43.45 kn. To reverse it, multiply knots by 1.150779 to get mph.
Conversion table
| Miles per hour (mph) | Knots (kn) |
|---|---|
| 1 | 0.86897624 |
| 5 | 4.3448812 |
| 10 | 8.6897624 |
| 20 | 17.3795248 |
| 30 | 26.0692872 |
| 40 | 34.7590496 |
| 50 | 43.448812 |
| 60 | 52.1385744 |
| 70 | 60.8283368 |
| 100 | 86.897624 |
How to convert online
- Type the number of miles per hour into the first box.
- Read the knot value instantly in the second box.
- Or enter a knot value to convert back to mph — it works both ways.
Use the Mile per Hour to Knot Converter — free and instant in your browser.
Where this conversion is used
Knots are the standard speed unit in aviation, marine navigation and meteorology, so converting from mph is common when reading boat and aircraft speeds, wind forecasts and hurricane reports that mix everyday mph figures with nautical knots.
Worked example
Suppose a weather bulletin reports sustained winds of 75 mph — the threshold for a Category 1 hurricane — and you want the figure in knots. Apply the formula: 75 × 0.86897624 = 65.17 kn, which lines up with the 64-knot hurricane definition used by mariners. A 40 mph gale converts to 40 × 0.86897624 = 34.76 kn. Reversing it, a 20-knot sailing breeze is 20 × 1.150779 = 23.02 mph. Because a knot is one nautical mile per hour, the same speed always reads as a smaller number in knots than in mph.
FAQ
How many knots are in a mph?
One mile per hour equals 0.86897624 knots. Multiply mph by 0.86897624 — for example, 10 mph = 8.6897624 kn.
Why is a knot faster than a mph?
A knot is one nautical mile (1,852 m) per hour, while a mph is one statute mile (1,609.344 m) per hour, so each knot covers more ground — hence mph values shrink when expressed in knots.
How do I convert knots back to mph?
Multiply knots by 1.150779 (or divide by 0.86897624). So 10 kn = 11.51 mph.
Related converters
- Knot to Mile per Hour Converter
- Mile per Hour to Meter per Second Converter
- Mile per Hour to Kilometer per Hour Converter
- Mile per Hour to Foot per Second Converter
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