Written by Muneeb Rana · Last updated 26 October 2026
Quick answer: MPH vs km/h: miles per hour is used for road speeds mainly in the United States and the United Kingdom; kilometres per hour is used almost everywhere else. One mile is exactly 1.609344 km, so 60 mph is about 96.6 km/h and 100 km/h is about 62.1 mph. Speedometer PRO can show either.
TL;DR
- 1 mile = 1.609344 km exactly.
- mph: US, UK and a few others.
- km/h: most of the world.
- Quick rule: km/h × 0.6 ≈ mph.
- Switch units in the app.
MPH vs km/h definitions
Miles per hour counts statute miles travelled in an hour; kilometres per hour counts kilometres. NIST lists the mile as exactly 1.609344 km.
Km/h vs mph conversion table
| mph | km/h |
|---|---|
| 20 | 32.2 |
| 30 | 48.3 |
| 40 | 64.4 |
| 50 | 80.5 |
| 60 | 96.6 |
| 70 | 112.7 |
| 80 | 128.7 |
Who uses which
The US and UK use mph for road signs; a handful of other territories do too. Canada, Australia and most of Europe and Asia use km/h. Wikipedia lists countries by unit.
Mental shortcuts
km/h to mph: multiply by 0.6 (or ×5 ÷8). mph to km/h: multiply by 1.6 (×8 ÷5). For exact numbers use km/h to mph or mph to km/h.
Switching units
In Speedometer PRO, choose MPH or KM/H in settings. Set it before driving, especially in rental cars abroad.
Speed limits side by side
Common limits line up imperfectly: 30 mph is about 48 km/h, 50 mph about 80 km/h, 70 mph about 113 km/h. Countries using km/h often set 50 km/h in towns, 80–100 km/h on rural roads and 110–130 km/h on motorways, though this varies; check local rules.
Precision
Because 1 mile is exactly 1.609344 km, conversions are exact maths. Rounding to 1.6 introduces an error of about 0.6%, which is fine for mental arithmetic but adds up in long-distance calculations.
Dual-scale speedometers
Cars sold in mph countries often show km/h on a smaller inner scale, and vice versa. Digital dashboards can usually switch units in settings. When driving abroad, switching both your car display and your app to the local unit avoids mental conversions.
Other units
Knots for boats and planes (what is a knot), m/s for science.
Related: MPH guide: speed units explained · KMH to MPH converter · MPH to KMH converter · Speedometer MPH and KM/H units · What does mph mean? · What is a knot in speed? · Knots to MPH converter · MPH to meters per second converter
Get Speedometer PRO on Google Play · Download on the App Store · Set it up before you move; never handle your phone while driving.
Sources
- Unit conversion (NIST Office of Weights and Measures): nist.gov (accessed 26 October 2026)
- Miles per hour (Wikipedia): en.wikipedia.org (accessed 26 October 2026)
- Kilometres per hour (Wikipedia): en.wikipedia.org (accessed 26 October 2026)
- Speed limits by country (Wikipedia): en.wikipedia.org (accessed 26 October 2026)
FAQ
Is mph faster than km/h?
A mile is longer than a kilometre, so 1 mph is about 1.61 km/h. The same speed has a bigger number in km/h.
How do I convert km/h to mph quickly?
Multiply by 0.6 for a rough answer, or 0.621371 for precision.
Which countries use mph?
Mainly the United States and the United Kingdom, plus some territories.
Does Speedometer PRO support both?
Yes, it shows speed in MPH or KM/H.
What is 100 km/h in mph?
About 62.1 mph.