The mph to km/h factor
One mile equals 1.60934 kilometers, so to convert miles per hour to kilometers per hour you multiply by 1.60934. For example, 60 mph × 1.60934 = 96.56 km/h. Need the reverse? Use the km/h to mph calculator.
The factor is the mile itself: since 1959 the international mile has been defined as exactly 1,609.344 metres. Speed is distance over time and the time unit is the same on both sides, so the conversion is simply the distance factor applied unchanged — no extra step for the hours.
How to use this calculator
Enter a speed in mph and the converter instantly shows the equivalent in km/h, rounded to two decimals — handy when driving abroad or reading car specs. Just multiply mph by 1.60934.
Worked examples: a 25 mph residential limit is 40.23 km/h, close enough to the 40 km/h used across much of Europe. A 5 mph jog is 8.05 km/h. A 155 mph limiter is 249.4 km/h, the familiar 250 km/h electronic ceiling on German saloons.
For mental arithmetic, multiply by 1.6, or add half again plus a tenth: 60 + 30 + 6 = 96, within a whisker of 96.56. Going the other way, a 100 km/h limit is 62 mph and 130 km/h is 81 mph. Dashboards in the UK and US show mph as the large numbers and km/h as an inner ring, so check which scale you are reading before you rely on it abroad.
Keep the miles to km calculator nearby for the rest of the same job.
MPH to km/h reference table
Common conversions:
| mph | km/h |
|---|---|
| 30 mph | 48.28 km/h |
| 50 mph | 80.47 km/h |
| 60 mph | 96.56 km/h |
| 70 mph | 112.65 km/h |
| 100 mph | 160.93 km/h |
Speed limits are the practical use of this table. Typical km/h limits are 50 in town, 90 to 110 on rural roads and 120 to 130 on motorways, which map to roughly 31, 56 to 68 and 75 to 81 mph. Speedometers are legally allowed to over-read but never under-read, so an indicated 70 mph is often nearer 67 mph of true speed. To reverse the conversion, use the km/h to mph calculator.
Frequently asked questions
- How do I convert mph to km/h?
- Multiply the mph value by 1.60934. For example, 60 mph × 1.60934 = 96.56 km/h.
- What is 60 mph in km/h?
- 60 mph equals about 96.56 km/h.
- How many km/h is 70 mph?
- 70 mph equals about 112.65 km/h — a common highway limit.
- Why is the factor 1.60934?
- Because one mile is exactly 1.609344 kilometers, so speeds scale by the same factor.
- Which countries use km/h and which use mph?
- Almost every country posts limits in km/h; the main exceptions are the United States and the United Kingdom, which use mph. Ireland switched to km/h in 2005, so a car driven north from Dublin crosses into mph signage at the border.