MPH to KM/H: Speed Conversion Guide for International Driving
MPH vs KM/H: Who Uses What?
Most of the world posts speed limits and measures vehicle speed in kilometers per hour. A smaller group of countries still uses miles per hour. Knowing which system you are in helps you interpret signs correctly.
Countries that use mph for speed limits and road signs include the United States, the United Kingdom, Myanmar (Burma), and Liberia. In the UK, speed limits are in mph even though many other measurements have gone metric. In the US, mph is used everywhere for road speed.
Countries that use km/h include almost everyone else: all of continental Europe, Canada, Mexico, Australia, New Zealand, Japan, China, India, Brazil, South Africa, and the vast majority of nations. When you see a number on a speed sign abroad, it is almost always in km/h unless you are in the US, UK, Myanmar, or Liberia.
The Conversion Formula
Converting between mph and km/h is straightforward once you know the factors. One mile equals about 1.609 kilometers, so speed in miles per hour can be converted to kilometers per hour by multiplying by 1.609. Going the other way, divide km/h by 1.609 or multiply by 0.621 to get mph.
- mph to km/h: multiply mph by 1.609. Example: 60 mph x 1.609 = 96.54 km/h.
- km/h to mph: multiply km/h by 0.621 (or divide by 1.609). Example: 100 km/h x 0.621 = 62.1 mph.
For quick mental estimates, remember that 60 mph is close to 97 km/h, and 100 km/h is close to 62 mph. That makes 50 km/h roughly 31 mph, and 80 km/h about 50 mph.
Speed Limit Comparison by Country
Highway and motorway speed limits vary by country. The table below shows typical highway limits in km/h and the approximate equivalent in mph so you can compare them to what you are used to.
| Country | Highway limit (km/h) | Approx. (mph) |
|---|---|---|
| Germany (autobahn, unrestricted sections) | No limit (advisory 130) | No limit (advisory 81) |
| UK | 70 mph (signed in mph) | 70 |
| France | 130 (110 in rain) | 81 (68 in rain) |
| Japan | 100 | 62 |
| Australia | 110 (some 100) | 68 (62) |
| Canada | 100 or 110 (varies by province) | 62 or 68 |
| US | 55 to 85 mph (signed in mph, varies by state) | 55 to 85 |
Note: Germany has sections of autobahn with no mandatory speed limit; 130 km/h is only an advisory. Always obey local signs and conditions.
Common Speed Conversions
Use this table for quick reference when you see a speed in one unit and need the other. Values are rounded for readability.
| mph | km/h |
|---|---|
| 20 | 32 |
| 30 | 48 |
| 40 | 64 |
| 50 | 80 |
| 55 | 89 |
| 60 | 97 |
| 65 | 105 |
| 70 | 113 |
| 75 | 121 |
| 80 | 129 |
| 90 | 145 |
| 100 | 161 |
| 110 | 177 |
| 120 | 193 |
Tips for Driving with Unfamiliar Speed Units
When you are in a country that uses the other unit than you are used to, a few habits can help you stay safe and within the limit.
- Check the speedometer. Most modern cars, including rental cars, show both mph and km/h. The inner scale is often in one unit and the outer in the other. Glance at which scale matches the road signs so you do not mix them up.
- Use simple mental rules. If you think in mph and signs are in km/h, "half and add 10" gives a rough mph from km/h: 80 km/h is about 40 + 10 = 50 mph. For mph to km/h, roughly double and add half again: 60 mph is about 60 + 30 = 90 km/h (actual 97).
- Let GPS help. Navigation apps usually show speed in the unit used locally and can warn you when you exceed the limit. Rely on them as a backup, but still watch the actual signs.
For a quick conversion without a calculator: to go from mph to km/h, multiply mph by 8 and divide by 5. So 50 mph x 8 / 5 = 80 km/h. To go from km/h to mph, multiply km/h by 5 and divide by 8. So 80 km/h x 5 / 8 = 50 mph. This uses the fact that 1.6 is close to 8/5.
Special Case: The UK
The UK uses miles per hour for speed limits and road signs, so Americans and others used to mph will see familiar numbers. Distances on road signs are also in miles. The main confusion for visitors is that the UK has otherwise adopted metric for many things: fuel is sold in liters, and weight can be in kilograms. So you might see mph on the motorway but liters per 100 km in the car manual. Keep in mind that speed and distance on the road are still in miles and mph.
Frequently Asked Questions
How do I convert mph to km/h?
Multiply mph by 1.609. For example, 60 mph equals 96.6 km/h. For a quick estimate, add 60% to the mph value.
What is 100 km/h in mph?
100 km/h equals approximately 62.1 mph.
Does the UK use mph or km/h?
The UK uses miles per hour for speed limits and road signs, even though it has partially adopted the metric system for other measurements.
What is the fastest speed limit in the world?
The highest posted speed limit is 160 km/h (99 mph) on some highways in the UAE. Germany's autobahn famously has sections with no speed limit at all.
Do rental cars abroad show both mph and km/h?
Most modern cars display both units on the speedometer. If yours only shows km/h, remember that 50 km/h is about 30 mph and 100 km/h is about 60 mph.