km/h to mph — convert kilometres per hour to miles per hour
Exact 1 ÷ 1.609344 = 0.62137119
1 kilometre per hour in other units
| Metres per second | 0.27777778 | m/s |
|---|---|---|
| Miles per hour | 0.62137119 | mph |
| Feet per second | 0.91134442 | ft/s |
| Knots | 0.5399568 | kn |
km/h to mph at a glance
| Kilometres per hour | Miles per hour |
|---|---|
| 1 km/h | 0.62137119 mph |
| 2 km/h | 1.242742 mph |
| 3 km/h | 1.864114 mph |
| 5 km/h | 3.106856 mph |
| 10 km/h | 6.213712 mph |
| 20 km/h | 12.427424 mph |
| 25 km/h | 15.53428 mph |
| 50 km/h | 31.06856 mph |
| 100 km/h | 62.137119 mph |
| 250 km/h | 155.342798 mph |
| 500 km/h | 310.685596 mph |
| 1,000 km/h | 621.371192 mph |
How to convert kilometres per hour to miles per hour
Multiply by 0.62137119 — one kilometre per hour is 0.62137119 miles per hour. That factor is exact: it comes from the definition of the units rather than from a measurement, so it will not change and does not need rounding.
Working 1 ÷ 1.609344 = 0.62137119
Questions
How many miles per hour are in a kilometre per hour?
One kilometre per hour is 0.62137119 miles per hour. This figure is exact — it comes from the definition of the unit, not a measurement.
What is 1 kilometre per hour in miles per hour?
1 kilometre per hour is 0.62137119 miles per hour. The working is 1 ÷ 1.609344 = 0.62137119.
What is a knot?
One nautical mile per hour — and a nautical mile is one minute of latitude, fixed at exactly 1,852 metres. That is the whole point of it: a ship making 10 knots for six hours has covered one degree of latitude, which you can read straight off a chart without converting anything.
Why do sailors and pilots say "knots" and not "knots per hour"?
Because the "per hour" is already inside the word. A knot is a speed, not a distance, so "knots per hour" would be an acceleration. The name comes from the knotted rope once paid out behind a ship and counted against a sand glass.
What's the quick way to convert mph to km/h in my head?
Multiply by 1.6, or add 60%. For the other direction, take away a third and then a little more. Fifty mph is 80 km/h, 60 is 97, 70 is 113 — worth remembering if you drive across a border where the signs change.
Why isn't Mach on this page?
Because it is not a fixed unit. Mach 1 is the local speed of sound, which falls as air gets colder — around 1,235 km/h at sea level but closer to 1,062 km/h in the stratosphere where airliners cruise. A single conversion factor would be wrong nearly everywhere.