MPH to km/h converter
Type mph or km/h and watch both update live.
1 mph = 1.609344 km/h exactly.
Mph to kmh conversion table
| Miles per hour | Kilometers per hour |
|---|---|
| 5 | 8 |
| 10 | 16.1 |
| 15 | 24.1 |
| 20 | 32.2 |
| 25 | 40.2 |
| 30 | 48.3 |
| 35 | 56.3 |
| 40 | 64.4 |
| 45 | 72.4 |
| 50 | 80.5 |
| 55 | 88.5 |
| 60 | 96.6 |
| 65 | 104.6 |
| 70 | 112.7 |
| 75 | 120.7 |
| 80 | 128.7 |
| 85 | 136.8 |
| 90 | 144.8 |
| 100 | 160.9 |
| 110 | 177 |
| 120 | 193.1 |
- Live two-way conversion
- Common speed limits
- Table from 5 to 120 mph
How to convert mph to kmh
- Type a value in the mph box.
- The km/h box updates as you type.
- Check the table for a familiar speed limit.
One speedometer, two scales
Speed is just distance over time, so converting mph to km/h uses the same fixed 1.609344 ratio as converting miles to km. The US and UK still post speed limits in mph, while almost every other country, including Canada, posts them in km/h, which is why cars sold internationally are often built with both scales on the same dial.
Airplane and boat speeds are usually given in knots instead of either one, a separate unit based on the nautical mile, so pilots and sailors are doing a third kind of conversion on top of this one.
US speed limits in km/h
| Speed limit | mph | km/h |
|---|---|---|
| School zone | 25 mph | 40.2 km/h |
| Old national limit | 55 mph | 88.5 km/h |
| Typical highway | 65 mph | 104.6 km/h |
| Higher rural highway | 75 mph | 120.7 km/h |
| Some rural interstates | 80 mph | 128.7 km/h |
A quick way to estimate without a calculator
- Multiply mph by 1.6 for a fast estimate. For 65 mph: 65 x 1.6 is 104, close to the exact 104.6 km/h.
- That shortcut is within about half a percent for typical road speeds, close enough to read a foreign speed limit sign at a glance.
Common mistakes
- Assuming a bigger km/h number means a genuinely faster car. A 100 km/h speed limit is not faster than a 60 mph one, it is about 62.1 mph, only a little quicker.
- Confusing this speed conversion with a distance conversion. Both use the same 1.609344 factor, but converting a distance in miles and converting a speed in mph are two different questions with the same underlying ratio.
- Using the 1.6 mental shortcut on a speeding ticket or legal calculation instead of the exact 1.609344 factor, which can matter right at a threshold speed.
MPH to km/h FAQ
How many km/h is 60 mph?
60 mph equals 96.6 km/h.
How many km/h is 70 mph?
70 mph, a common US highway speed, equals about 112.7 km/h.
Why is the factor 1.609344?
A mile is defined as exactly 1.609344 km, and speed carries the same ratio per hour.
Is this exact?
The underlying factor is exact. The table rounds to 1 decimal place for readability.
What is a 25 mph school zone in km/h?
25 mph equals about 40.2 km/h.
What is 55 mph in km/h?
55 mph, once the standard US national speed limit, equals about 88.5 km/h.
Why do some US car speedometers show both mph and km/h?
Cars built for both the US and international markets share one instrument cluster, so the outer ring is often marked in mph and the inner ring in km/h, or the reverse, on the same dial.
What is 80 mph in km/h?
80 mph equals about 128.7 km/h.