Every American driver knows MPH—but if you're traveling to Canada, Mexico, or anywhere else in the world, you need to understand KMH. Here's everything you need to know about converting between these speed units.
The Conversion Formula
Converting between miles per hour and kilometers per hour is simple.
MPH to KMH:
km/h = mph × 1.609344
KMH to MPH:
mph = km/h ÷ 1.609344
Common Speed Conversions
| Miles per Hour (mph) | Kilometers per Hour (km/h) |
|---|---|
| 25 | 40.23 |
| 35 | 56.33 |
| 55 | 88.51 |
| 65 | 104.61 |
| 75 | 120.70 |
| 100 | 160.93 |
US Speed Limits
| Road Type | Typical Speed Limit (mph) | Equivalent (km/h) |
|---|---|---|
| Residential Street | 25 | 40 |
| School Zone | 15-25 | 24-40 |
| Urban Arterial | 35-45 | 56-72 |
| Rural Highway | 55 | 89 |
| Interstate Highway | 65-75 | 105-121 |
International Speed Limits
- Canada: Most highways 100-110 km/h (62-68 mph)
- Mexico: Highways 100-120 km/h (62-75 mph)
- Europe: Motorways 110-130 km/h (68-81 mph)
- Japan: Expressways 80-100 km/h (50-62 mph)
Fuel Economy Conversions
Fuel economy is measured differently around the world:
- US: Miles per gallon (mpg)
- Canada/Europe: Liters per 100 kilometers (L/100km)
Conversion: 1 mpg ≈ 0.425 L/100km
Quick Tips for Travelers
- Rental cars: Many modern cars display both MPH and KMH
- GPS: Set your navigation to display your preferred unit
- Approximation: KMH ≈ MPH × 1.6
- Use our converter: For precise results, use UnitFig's speed converter
Related Tools
FAQ
Why does the US use MPH?
MPH is part of the US customary system, which was adopted from British imperial units. It remains the standard for road travel in the United States.
Do US speedometers show KMH?
Most modern US vehicles have dual-scale speedometers showing both MPH and KMH, with MPH being more prominent.
What's the difference between MPH and km/h?
MPH measures miles per hour, while km/h measures kilometers per hour. 1 mile is longer than 1 kilometer (1 mile = 1.609 km).