justyourconvertmph to km/h
Miles per hour to kilometers per hour, exact.
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- Exact NIST Factors
mph to km/h
Convert miles per hour to kilometers per hour
1 mile per hour = 1.609344 kilometers per hour
Formula: km/h = mph × 1.609344
Miles per hour to kilometers per hour table
| Miles per hour (mph) | Kilometers per hour (km/h) |
|---|---|
| 1 | 1.609344 |
| 2 | 3.218688 |
| 3 | 4.828032 |
| 4 | 6.437376 |
| 5 | 8.04672 |
| 6 | 9.656064 |
| 7 | 11.265408 |
| 8 | 12.874752 |
| 9 | 14.484096 |
| 10 | 16.09344 |
| 15 | 24.14016 |
| 20 | 32.18688 |
| 25 | 40.2336 |
| 50 | 80.4672 |
| 100 | 160.9344 |
Calculated on your device with exact factors from NIST and the SI.
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How to convert mph to km/h
Three steps, all in your browser.
- 1
Type a number
Enter a value in either box; the other updates instantly.
- 2
Pick the units
Switch units or swap them around.
- 3
Copy the result
Copy the answer or read it off the conversion table.
mph to km/h: what to know
Miles per hour (mph) is the road speed unit in the United States and the UK, and kilometers per hour (km/h) is used almost everywhere else. To convert mph to km/h, multiply by 1.609344. The factor is exact, because the international mile is defined as exactly 1609.344 m.
Worked examples: 25 mph (a common US residential limit) is 40.23 km/h; 55 mph is 88.51 km/h; 70 mph (the UK motorway limit) is 112.65 km/h; a 100 mph fastball is 160.93 km/h. Wind speeds and hurricane categories are often given in mph in US forecasts, and the same factor applies.
Related speed units work the same way: 1 mph is exactly 0.44704 meters per second and 1.46667 feet per second, and a knot (nautical mile per hour) is 1.15078 mph. All of these are in the full unit converter. Because the factor is exact, converting a value to km/h and back always returns the original mph figure.
Popular uses
- Converting US and UK speed limits for visitors
- Comparing car and motorcycle performance figures
- Reading sports speeds such as pitches and serves
- Converting wind and storm speeds from US forecasts
Tips for the best result
- Quick estimate: mph × 1.6 (or × 8 ÷ 5).
- Round speed limits to whole numbers; signs never show decimals.
- Use knots for boats and aircraft, not mph.
- When renting a car abroad, check which scale the speedometer shows before you set off.
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