Convert kilometre per hour to mile per hour
1 kilometre per hour = 0.6213712 miles per hour. Enter any value below for an exact conversion.
1 km/h =
0.6213712 mph
miles per hour
Need the reverse? Convert mile per hour to kilometre per hour →
Formula
1 kilometre per hour = 0.6213712 miles per hour mile per hour = kilometres per hour × 0.6213712 kilometre per hour = miles per hour × 1.609344
kilometre per hour to mile per hour conversion table
About converting kilometres per hour to miles per hour
Kilometres per hour to miles per hour helps US and UK drivers interpret metric speed limits and car specs. Multiply km/h by 0.621 to get mph — so 100 km/h is about 62 mph.
Method & sources
Conversions use exact legal definitions rather than rounded approximations: 1 inch = 2.54 cm and 1 pound = 0.45359237 kg (fixed by the 1959 international yard and pound agreement), 1 mile = 1.609344 km, and 1 US liquid gallon = 3.785411784 litres. Temperatures convert with °F = °C × 9⁄5 + 32 and K = °C + 273.15. Results are rounded only for display.
- NIST Special Publication 811 — Guide for the Use of the SI
- NIST Handbook 44, Appendix C — General Tables of Units of Measurement
Page last updated: October 1, 2026
Frequently asked questions
How many miles per hour are in a kilometre per hour?
One kilometre per hour equals 0.6213712 miles per hour. So 10 kilometres per hour is 6.213712 miles per hour. Use the converter above for any value.
What is the formula to convert kilometres per hour to miles per hour?
1 kilometre per hour = 0.6213712 miles per hour mile per hour = kilometres per hour × 0.6213712 kilometre per hour = miles per hour × 1.609344
Is the kilometre per hour-to-mile per hour conversion exact?
Yes. The conversion factor between kilometres per hour and miles per hour is defined exactly, so results are precise — only rounded for display.
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