To convert mph to km/h, multiply by 1.609344. 30 mph is 48.28 km/h, 60 mph is 96.56 km/h, and 70 mph is 112.65 km/h.
Speed limits and speedometers in the US and UK are in mph. Visitors from metric countries, and anyone comparing car specs or wind speeds, need it in km/h.
How to use the mph to km/h converter
- Type the value in mph into the box. Decimals are fine.
- The result in km/h updates as you type, along with the working.
- Need the other way? Switch the direction menu, or open the km/h to mph converter.
Formula
Because a mile is exactly 1.609344 km, 1 mph is exactly 1.609344 km/h (and 0.44704 m/s). The hour is the same in both units, so only the distance changes.
Worked example
A US highway limit is 65 mph. What is that in km/h?
- 65 × 1.609344 = 104.61.
- Result: 104.6 km/h, close to the 100 km/h limit on many metric highways.
Mph to km/h chart
Common values, rounded to 2 decimal places.
| Mph (mph) | Km/h (km/h) |
|---|---|
| 5 mph | 8.05 km/h |
| 10 mph | 16.09 km/h |
| 15 mph | 24.14 km/h |
| 20 mph | 32.19 km/h |
| 25 mph | 40.23 km/h |
| 30 mph | 48.28 km/h |
| 35 mph | 56.33 km/h |
| 40 mph | 64.37 km/h |
| 45 mph | 72.42 km/h |
| 50 mph | 80.47 km/h |
| 55 mph | 88.51 km/h |
| 60 mph | 96.56 km/h |
| 65 mph | 104.61 km/h |
| 70 mph | 112.65 km/h |
| 75 mph | 120.7 km/h |
| 80 mph | 128.75 km/h |
| 90 mph | 144.84 km/h |
| 100 mph | 160.93 km/h |
| 120 mph | 193.12 km/h |
| 150 mph | 241.4 km/h |
Where mph is used
- Roads: US, UK and a few other countries. Typical US limits: 25 mph residential (40.2 km/h), 55 mph (88.5 km/h), 70 mph (112.7 km/h).
- Weather: US forecasts give wind in mph; a Category 1 hurricane starts at 74 mph (119 km/h).
- Sports: baseball pitches and tennis serves in the US.
- Treadmills: 6 mph is a 10-minute mile, or 9.66 km/h. For running paces, see the pace calculator.
Quick mental math
Multiply by 1.6, or add 60%: 50 mph + 30 = 80 km/h (exact: 80.47).
Related conversions
Going the other way: km/h to mph converter. Related pages: . For other units in the same family, use the full speed converter.
Caveats and assumptions
- Results show up to 10 significant digits; the chart is rounded for reading. Keep full precision for engineering, medical or legal work.
Frequently asked questions
What is 60 mph in km/h?
96.56 km/h.
What is 70 mph in km/h?
112.65 km/h.
How many km/h is 1 mph?
Exactly 1.609344 km/h.
Is mph the same as knots?
No. 1 knot is 1 nautical mile per hour, 1.852 km/h or 1.151 mph. The speed converter handles knots.
Sources
- NIST SP 811 Appendix B.9 — Conversion factors — mile per hour to kilometer per hour and meter per second
- NIST — SI Units: Length (1959 definition of the inch) — 1 in = 25.4 mm exactly
This calculator gives estimates for planning and education. Check measurements, local codes, supplier specs and your school's official policy before relying on a result. See our disclaimer and how we build and check calculators.