Miles Per Hour to Kilometers Per Hour Converter
Convert miles per hour to kilometers per hour instantly with this free miles per hour to kilometers per hour converter. Enter any value to get an accurate speed conversion, plus the formula, the conversion factor and a full reference table.
What is 1 mile per hour in kilometers per hour?
1 mile per hour is equal to exactly 1.609344 kilometers per hour.
1 × 1.609344 = 1.609344 kilometers per hour
1 mile per hour = 1.609344 kilometers per hour
Miles per hour to Kilometers per hour formula
km/h = mph × 1.609344
The miles per hour to kilometers per hour conversion factor is 1.609344, which is exact by definition. 1 mile per hour = 1.609344 kilometers per hour, and 1 kilometer per hour = 0.621371192237 miles per hour.
Worked examples
- 2 miles per hour = 3.218688 kilometers per hour — 2 × 1.609344 = 3.218688 kilometers per hour
- 6 miles per hour = 9.656064 kilometers per hour — 6 × 1.609344 = 9.656064 kilometers per hour
- 10 miles per hour = 16.09344 kilometers per hour — 10 × 1.609344 = 16.09344 kilometers per hour
Miles per hour to Kilometers per hour conversion table
Every value below is calculated with the exact conversion factor and rounded for display.
| Miles per hour (mph) | Kilometers per hour (km/h) |
|---|---|
| 1 mph | 1.609344 km/h |
| 2 mph | 3.218688 km/h |
| 3 mph | 4.828032 km/h |
| 4 mph | 6.437376 km/h |
| 5 mph | 8.04672 km/h |
| 6 mph | 9.656064 km/h |
| 7 mph | 11.265408 km/h |
| 8 mph | 12.874752 km/h |
| 9 mph | 14.484096 km/h |
| 10 mph | 16.09344 km/h |
| 12 mph | 19.312128 km/h |
| 15 mph | 24.14016 km/h |
| 20 mph | 32.18688 km/h |
| 25 mph | 40.2336 km/h |
| 30 mph | 48.28032 km/h |
| 50 mph | 80.4672 km/h |
| 75 mph | 120.7008 km/h |
| 100 mph | 160.9344 km/h |
| 500 mph | 804.672 km/h |
| 1,000 mph | 1,609.344 km/h |
When you need to convert miles per hour to kilometers per hour
- Reading road signs and speed limits abroad.
- Comparing running or cycling pace with training plans from another country.
- Interpreting wind speeds in forecasts and aviation or marine reports.
Common mistakes to avoid
- Dividing when you should multiply. Because 1 mile per hour = 1.60934 kilometers per hour, the answer should be larger than the number you started with.
- Rounding too early. Convert first at full precision, then round the final answer to the precision the task actually needs.
How precise does the answer need to be?
Round only at the end, and only to the precision your task actually needs. The converter above keeps full double precision internally and rounds for display.
How these units are defined
- Mile per hour (mph): The road-speed unit in the US and UK. This unit's relationship to the SI base unit is exact by definition, so no rounding enters the conversion factor.
- Kilometer per hour (km/h): The road-speed unit in metric countries. This unit's relationship to the SI base unit is exact by definition, so no rounding enters the conversion factor.
Related conversions
Frequently asked questions
- What is 1 mile per hour in kilometers per hour?
- 1 mile per hour is equal to 1.609344 kilometers per hour.
- How many miles per hour are in one kilometer per hour?
- There are 0.621371192 miles per hour in 1 kilometer per hour.
- How do you convert miles per hour to kilometers per hour?
- Multiply the number of miles per hour by 1.609344 — or use the formula km/h = mph × 1.609344.
- What is 6 miles per hour in kilometers per hour?
- 6 miles per hour is 9.656064 kilometers per hour. 6 × 1.609344 = 9.656064 kilometers per hour.
- Is the miles per hour to kilometers per hour conversion exact?
- Yes. The relationship is fixed by definition, so 1.609344 is an exact conversion factor — only the displayed result is rounded.