km/h to mph Converter
To convert kilometers per hour to miles per hour, multiply by 0.621371192237334. For example, 100 km/h ≈ 62.14 mph, and 60 km/h ≈ 37.28 mph.
Formula
mph = km/h × 0.621371192237334
Reverse:
km/h = mph × 1.609344
Formula variables
- km/h — speed in kilometers per hour.
- mph — equivalent speed in miles per hour.
- 0.621371192237334 — the ratio between a mile and a kilometer. Both miles and hours are fixed by definition (1 mile = 1.609344 km exactly), so the factor is exact.
Worked Examples
Example 1: 100 km/h to mph
- Start: 100 km/h.
- Multiply: 100 × 0.621371192237334 = 62.1371192237334.
- Result: 100 km/h ≈ 62.137 mph.
Example 2: 60 km/h to mph
- Start: 60 km/h.
- Multiply: 60 × 0.621371192237334 = 37.28227153424004.
- Result: 60 km/h ≈ 37.282 mph.
Example 3: 120 km/h to mph
- Start: 120 km/h.
- Multiply: 120 × 0.621371192237334 = 74.56454306848008.
- Result: 120 km/h ≈ 74.565 mph. This is a common highway speed in many European countries.
Common Conversion Table
| km/h | mph |
|---|---|
| 10 | 6.214 |
| 20 | 12.427 |
| 30 | 18.641 |
| 40 | 24.855 |
| 50 | 31.069 |
| 60 | 37.282 |
| 80 | 49.710 |
| 100 | 62.137 |
| 120 | 74.565 |
| 130 | 80.778 |
| 160 | 99.419 |
Speed Limits Around the World
Because speed limits are quoted in km/h in most of the world and in mph in the US and UK, this conversion is used constantly by travelers. Here are the common speed limits in both units:
| Context | km/h | mph |
|---|---|---|
| Urban (EU typical) | 50 | 31 |
| Urban (UK) | 48 | 30 |
| Rural (EU typical) | 90 | 56 |
| Rural (UK) | 96 | 60 |
| Highway (US typical) | 105–121 | 65–75 |
| Highway (Germany recommended) | 130 | 81 |
| US Interstate max | 137 | 85 |
Real-World Uses
- Driving abroad: Speed limits on foreign roads are given in km/h; US and UK drivers convert mentally to gauge whether they are driving legally.
- Car specifications: Top speed, acceleration times, and test-track results are published in different units depending on the country.
- Aviation: Airspeed is typically in knots, but ground speed in flight planning is often given in km/h or mph depending on the operator.
- Sports: Motorsport broadcasts quote speeds in km/h for international events and in mph for US events.
Unit Definitions
Kilometer per hour (km/h)
A derived SI unit of speed. One km/h equals 1/3.6 m/s. It is the standard unit of speed for road transport in almost every country outside the United States and the United Kingdom.
Mile per hour (mph)
A customary unit of speed equal to one international mile per hour, which is exactly 0.44704 m/s. It is the standard unit of road speed in the US and the UK.
Accuracy and Rounding
Because both miles and hours are exact by definition, the km/h to mph conversion is exact. In practice, speedometers and speed limits are rounded to sensible values (multiples of 5 or 10), so a displayed value like "62 mph" is really the rounded version of 100 km/h.
Related Converters
- mph to km/h — the reverse conversion
- Knots to km/h — aviation and maritime speeds
- All Speed Converters
- Kilometers to Miles — distance version
Frequently Asked Questions
How do you convert km/h to mph?
Multiply the km/h value by 0.621371192237334. For example, 100 km/h × 0.621371192237334 ≈ 62.137 mph.
What is 60 km/h in mph?
60 km/h ≈ 37.282 mph. This is close to the UK urban speed limit of 30 mph.
What is 100 km/h in mph?
100 km/h ≈ 62.137 mph, commonly rounded to 62 mph for speed limit signs.
Is 100 km/h faster than 60 mph?
100 km/h is approximately 62.137 mph, so it is slightly faster than 60 mph.
How do you quickly estimate km/h in mph?
Divide by 1.6 or multiply by 0.625 for a rough estimate. For example, 80 km/h ≈ 50 mph (actual: 49.71 mph). This is accurate to within about 1%.