Speed conversion
Kilometres per hour to Miles per hour (km/h to mph)
Compare a speedometer or road-sign value in kilometres per hour with miles per hour. The converted value describes the same speed.
1 km/h ≈ 0.6214 mph — the calculator keeps the stored factor; this summary may be rounded.
A speed reading of 100 km/h
- Starting measurement
- 100 km/h
- Converted value (rounded if needed)
- 62.1371 mph
Use the unit shown on the road sign and your speedometer when driving. A rounded chart value is a reference, not a margin to add to a posted limit.
Kilometres per hour to Miles per hour conversion chart
| kilometres per hour | miles per hour |
|---|---|
| 10 km/h | 6.2137 mph |
| 20 km/h | 12.4274 mph |
| 30 km/h | 18.6411 mph |
| 40 km/h | 24.8548 mph |
| 50 km/h | 31.0686 mph |
| 60 km/h | 37.2823 mph |
| 70 km/h | 43.496 mph |
| 80 km/h | 49.7097 mph |
| 90 km/h | 55.9234 mph |
| 100 km/h | 62.1371 mph |
| 110 km/h | 68.3508 mph |
| 120 km/h | 74.5645 mph |
| 130 km/h | 80.7783 mph |
| 200 km/h | 124.274 mph |
How to convert by hand
Reference relationship (display may be rounded)
1 km/h = 0.621371192 mph
- Multiply the amount in kilometres per hour by the number of miles per hour per unit.
- Use the calculator for the stored precision; copying a short displayed factor introduces extra rounding.
- Round the result to suit your measurement, after completing the calculation.
Related conversions
About kilometres per hour and miles per hour
A converted speed describes the same motion in a different unit. Keep speed separate from pace, which is time per distance, and from travel time, which also needs a distance.
Kilometre per hour
MetricA speed covering one kilometre in one hour if maintained. Converting it changes the unit, not the journey time.
Commonly used for: Metric speedometers, road signs and cycling speeds.
Mile per hour
US / ImperialA speed covering one land mile in one hour if maintained. Miles per hour use land miles, unlike knots.
Commonly used for: US and UK road speeds and speed comparisons in forecasts.
Questions
Does this tell me how long a journey will take?
No. Travel time also needs distance and an appropriate average speed. A speed conversion alone does not account for stops, traffic or changes in speed.
How do I convert miles per hour back to kilometres per hour?
Enter the value in the miles per hour field above to work backwards, or open the Miles per hour to Kilometres per hour converter. This uses the stored factors rather than dividing by a rounded number copied from the chart.
Why might the chart and calculator show different decimal places?
The chart uses a compact rounded display. The editable calculator can show up to six decimal places and uses the factors or temperature formulas stored in the library. More displayed digits do not make the original measurement more precise.
Precision and source
The calculator uses stored conversion factors and temperature formulas, then rounds the result for display. A short decimal in a chart is not a claim of exactness. For a calculation with several steps, keep as much precision as the original measurement supports and round at the end.
Reference: NIST SP 811 conversion factors. Its alphabetical tables distinguish unit variants and temperature readings from intervals. Published by ToolsNow. Report a conversion problem.
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