Speed Converter
Convert between common speed units.
How to use the Speed Converter
- Type the number in the Value field. The page opens on km/h to mph with 1 filled in.
- Pick the unit you have in the From list and the unit you want in the To list.
- The converted figure appears under the fields as you type, rounded to six decimal places.
Which of the four units belongs where
Metres per second is the physics unit. Kilometres per hour is the road unit across most of the world, with miles per hour in the United States and the United Kingdom. Knots stay with aviation and shipping, because a knot is one nautical mile per hour.
The exact factors behind each conversion
A nautical mile is 1,852 metres and a statute mile is 1,609.344 metres, both fixed by international definition, so the figures below are exact rather than approximate.
| 1 unit | km/h | mph | knots |
|---|---|---|---|
| metre per second | 3.6 | 2.2369 | 1.9438 |
| kilometre per hour | 1 | 0.6214 | 0.5400 |
| mile per hour | 1.6093 | 1 | 0.8690 |
| knot | 1.852 | 1.1508 | 1 |
Rounded to four decimal places.
Frequently asked questions
Which unit do car speedometers use?
Kilometres per hour in most of the world, miles per hour in the US and UK.
Where are knots used?
In aviation and shipping. One knot is one nautical mile per hour, roughly 1.852 km/h.
How fast is 100 km/h in mph?
About 62.14 mph. The division is 100 by 1.609344, which gives 62.1371, so a 100 km/h motorway limit is a little over 62 mph.
What is 1 m/s in km/h?
Exactly 3.6 km/h. An hour holds 3,600 seconds and a kilometre holds 1,000 metres, so the factor is 3600 divided by 1000.
Can I see every unit at once?
No. One From unit and one To unit are shown at a time, so change the To list to read the same value in another unit.