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Convert mph to kn
1 mph = 0.868976241901 kn
Type a value in miles per hour and the answer in knots appears as you go. The conversion is exactly 0.868976241901 kn to the mile per hour, and it happens on your own machine — this page asks nothing of a server once it has loaded.
Where it runs
In your browser. The number you type is never part of a request.
Exact by definition
1 mph is exactly 0.868976241901 kn — a definition, not a rounded factor.
Answers as you type
No button, no wait. The worked answer is already on the page before any script runs.
Mile per hour and Knot
Miles per hour is the road speed of the United States and the United Kingdom, which is a rare pairing — the UK uses miles for road speed and metric for nearly everything else.
A knot is one nautical mile per hour, and a nautical mile is exactly 1,852 metres — originally one minute of latitude, so a knot relates speed directly to position on a chart. Its name comes from counting knots in a rope paid out behind a ship.
miles per hour to knots in practice
70 mph is 60.83 kn
— the British motorway limit.
30 mph is 26.07 kn
— a British urban speed limit.
miles per hour to knots at a glance
| mph | kn |
|---|---|
| 1 | 0.868976241901 |
| 2 | 1.7379524838 |
| 3 | 2.6069287257 |
| 5 | 4.3448812095 |
| 10 | 8.68976241901 |
| 20 | 17.379524838 |
| 50 | 43.448812095 |
| 100 | 86.8976241901 |
Every figure here is computed from the same definition the calculator uses, so the table cannot drift away from the answer above it.
Convert mph to kn: common questions
How many knots are in a mile per hour?
Exactly 0.868976241901. One mile per hour is 0.868976241901 knots, and the box above will do it for any figure you type.
Is this conversion exact, or rounded?
The ratio is exact. It is not a rounded constant typed into a table: it is derived from the definitions of the two units, so it agrees with any other correct converter to as many digits as you care to compare.
Why does another converter show a slightly different number?
Almost always rounding rather than disagreement. Many converters cut the answer to two or four decimals, and some carry a factor that was rounded before the multiplication rather than after. The figures here are computed from the exact definitions and only rounded on the way to the screen.
Where these figures come from
The claims this page makes about speed units are checkable, and these are the documents that settle them.
How this page works
The factor is a constant in the page and the arithmetic is four operations, so nothing is sent anywhere and nothing needs to be. The number you type never leaves the browser — there is no request for it to travel in.