How to Convert Knots to Miles per hour (kn to mph)
Speed conversions come up with expressway limits in km/h, foreign car specs in mph and wind speeds reported in knots by the Meteorological Service. This guide shows how to convert knots into miles per hour by hand, with examples and a quick-reference table.
The conversion
To convert knots to miles per hour, multiply the value by 1.1507784538. To go the other way, divide by the same number (or multiply by 0.8689769926). For a quick estimate, multiply by about 1.2.
Miles per hour = knots × 1.1507784538
Worked examples
- 3 kn = 3.4523 mph
- 12.5 kn = 14.3847 mph
- 75 kn = 86.3084 mph
Knots to Miles per hour table
| Knots | Miles per hour |
|---|---|
| 1 kn | 1.1508 mph |
| 2 kn | 2.3016 mph |
| 5 kn | 5.7539 mph |
| 10 kn | 11.5078 mph |
| 20 kn | 23.0156 mph |
| 25 kn | 28.7695 mph |
| 50 kn | 57.5389 mph |
| 100 kn | 115.0778 mph |
| 250 kn | 287.6946 mph |
| 500 kn | 575.3892 mph |
| 1,000 kn | 1,150.78 mph |
Common questions
Is kn to mph exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Miles per hour to Knots converter.
Mistakes to avoid
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Background
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
Writing the units next to every number while you work is the simplest way to avoid mistakes. If the units do not cancel to leave the one you want, the calculation is set up wrongly.
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
For any value, use the Knots to Miles per hour Converter or browse all speed converters.
Run your own numbers: Knots to Miles per hour Converter