Knots to mph converter
This tool converts speed between knots (kn) and miles per hour (mph) in both directions. A knot is one nautical mile per hour, the standard unit in shipping and aviation, while mph is the everyday road-speed unit in the US and UK. The converter makes it easy to read a vessel or wind speed in familiar terms.
How it works
It multiplies by the exact factor mph = knots × 1.150779. This comes from the two mile lengths: a nautical mile is 1852 metres and a statute mile is 1609.344 metres, so 1852 ÷ 1609.344 = 1.150779. To convert mph back to knots it divides by the same factor. Both fields are linked and update instantly as you type.
Worked examples
A yacht is sailing at 25 knots. To find its speed in mph:
25 × 1.150779 = 28.77 mph
A weather forecast reports a gale at 50 mph. To check that in knots (for a nautical chart or VHF weather broadcast):
50 ÷ 1.150779 = 43.45 kn
Quick reference table
| Knots (kn) | Miles per hour (mph) | Context |
|---|---|---|
| 1 | 1.15 | Gentle breeze |
| 10 | 11.51 | Slow vessel, calm conditions |
| 25 | 28.77 | Typical sailing yacht at pace |
| 30 | 34.52 | Fast powerboat / strong gale |
| 60 | 69.05 | Jet aircraft taxiing |
| 100 | 115.08 | Small aircraft cruise speed |
| 500 | 575.39 | Commercial jet cruise speed |
Why knots and mph coexist
The nautical mile is defined as one minute of arc along a meridian of latitude — making it a direct measurement of position on the globe. This geometric link to navigation charts is why the unit has persisted in shipping and aviation even in countries that otherwise use the metric system. Speed in knots therefore directly relates to how many minutes of latitude you cover per hour, which is a useful mental model for chart navigation.
Miles per hour, on the other hand, are the unit of everyday road speed in the US and UK and appear on weather forecasts, car speedometers, and road signs in those countries. When reading a marine weather bulletin or VHF channel 16 broadcast in a US or UK port, wind speeds are often given in knots; comparing them to a local mph speed limit or storm warning headline requires this conversion.
Common contexts for this conversion
- Sailing and motor cruising — checking vessel speed against weather forecasts or tide tables that use different units
- Aviation — light aircraft airspeed indicators in knots; local wind reports at non-international airfields sometimes in mph
- Weather interpretation — Beaufort Scale descriptions use knots; newspaper and broadcast reports in the US/UK use mph
- Drone and UAV operators — manufacturer specs may be in knots while local airspace restrictions are in mph
No data leaves your device — the conversion runs entirely in your browser.