Miles Per Hour to Knots
An instant miles per hour-to-knots converter, with the formula and a reference table below.
| Miles Per Hour | Knots |
|---|---|
| 1 mph | 0.868976 kn |
| 2 mph | 1.737952 kn |
| 3 mph | 2.606929 kn |
| 5 mph | 4.344881 kn |
| 10 mph | 8.689762 kn |
| 25 mph | 21.724406 kn |
| 50 mph | 43.448812 kn |
| 100 mph | 86.897624 kn |
How to use
- Enter a value in the Miles Per Hour field.
- The Knots figure appears immediately — no button to press.
- Typing in the Knots field converts back to Miles Per Hour the same way.
- Use the reference table for the values that come up most often.
Miles Per Hour to Knots formula
To convert miles per hour to knots, multiply by 0.868976242.
kn = mph × 0.868976242
Why this factor: the mile per hour and the knot are both defined against the meter per second, so dividing one definition by the other gives 0.868976242 directly. Both definitions are set out in full below.
To go the other way, divide by 0.868976242 — or use the Knots to Miles Per Hour converter, which is the same calculation reversed.
Worked example
Take 30 mph and multiply by the factor 0.868976242: the result is 26.069287 kn.
30 mph × 0.868976242 = 26.069287 kn
The converter above does this for any value you type, in either direction.
What is a mile per hour?
Miles per hour is the road speed unit of the United States and the United Kingdom.
Definition: Exactly 0.44704 meters per second, following from the exact 1,609.344 m mile.
Where it is used: US and UK speed limits and speedometers, plus baseball pitch and tennis serve speeds.
What is a knot?
A knot is one nautical mile per hour, the speed unit of ships and aircraft.
Definition: Exactly 1,852 meters per 3,600 seconds, so about 0.514444 m/s.
Where it is used: Marine and aviation speeds, and wind speed in forecasts for sailors and pilots.
Worth knowing: Say 'knots', never 'knots per hour' — the 'per hour' is already inside the unit.
Miles Per Hour vs Knots
The mile per hour is an imperial unit while the knot is a specialized unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many knots are in a mile per hour?
One mile per hour equals 0.868976242 knots.
What is the formula to convert miles per hour to knots?
Multiply the number of miles per hour by 0.868976242. To reverse it, divide by 0.868976242 instead.
How do I convert knots back to miles per hour?
Divide by 0.868976242, which is the same as multiplying by 1.15077945.
How many knots are in 10 miles per hour?
10 mph works out to 8.689762 kn.
Is there anything to watch out for with knots?
Say 'knots', never 'knots per hour' — the 'per hour' is already inside the unit.
How is the mile per hour defined?
Exactly 0.44704 meters per second, following from the exact 1,609.344 m mile.