kilometer per hour to mile per hour
Convert kilometer per hour (km/h) to mile per hour (mph). Use an editable speed converter, conversion formula, and reference table.
1 km/h = 0.6213711922 mph
Conversion formula
One kilometer per hour equals 0.6213711922 mile per hour. Multiply your value in kilometer per hour by this factor to get mile per hour. For the reverse conversion, divide by the same factor.
Worked example
To convert 5 kilometer per hour:5 × 0.6213711922 = 3.106855961 mph
Conversion table
| kilometer per hour (km/h) | mile per hour (mph) |
|---|---|
| 0.01 | 0.006213711922 |
| 0.1 | 0.06213711922 |
| 1 | 0.6213711922 |
| 2 | 1.242742384 |
| 5 | 3.106855961 |
| 10 | 6.213711922 |
| 25 | 15.53427981 |
| 50 | 31.06855961 |
| 100 | 62.13711922 |
| 1000 | 621.3711922 |
About these measurements
Speed is distance traveled per unit of time.
The base reference used here is the meter per second. One kilometer per hour is 0.2777777778 base units; one mile per hour is 0.44704 base units.
Important distinctions
Mach is excluded because the speed of sound depends on medium and temperature.
Precision
The converter uses stored conversion factors and floating-point arithmetic. Results display up to ten significant digits, switching to scientific notation for very small or large values. Keep the precision of your original measurement when reporting results.
Common questions
How do I convert km/h to mph?
Multiply the quantity in km/h by 0.6213711922. You can also type the value into the converter above.
Can I reverse the conversion?
Yes. Use the swap button or open the mile per hour to kilometer per hour converter.
Reference
NIST Guide to the SI — conversion factors and prefix conventions. SI prefixes scale units by powers of ten; the dimension-specific notes above describe the assumptions used on this page.
