1 kilometer = 0.6214 miles
Convert kilometers to miles with an exact, internationally defined factor — 1 km = 1,000 m (exact).
kilometers to miles
Computed with the exact factor · NIST SP 811
| Kilometer | Mile |
|---|---|
| 0.5 km | 0.3107 mi |
| 1 km | 0.6214 mi |
| 2 km | 1.243 mi |
| 3 km | 1.864 mi |
| 5 km | 3.107 mi |
| 10 km | 6.214 mi |
| 25 km | 15.53 mi |
| 50 km | 31.07 mi |
| 100 km | 62.14 mi |
Exact factor details
- Exact factor
- 1 km = 0.6214 mi (exact definition)
- Significant digits
- up to 4 significant digits shown
- Data source
- NIST SP 811 — verified against official tables
Why km to mi trips people up
Length conversions between metric and US customary units. The international yard and pound agreement of 1959 defined the foot as exactly 0.3048 meters, which makes every conversion below exact rather than approximate. One kilometer is 1,000 meters, about 0.621 miles. One mile is exactly 1,609.344 meters, or 5,280 feet.
Metric lengths (millimeter, centimeter, meter, kilometer) scale by powers of ten, while US customary units (inch, foot, yard, mile) relate by 12, 3, and 1,760. Because the inch is defined as exactly 2.54 centimeters, converting between the two systems never accumulates rounding error at the definition level — differences only appear in how results are displayed.
Use the quick-reference table for the amounts people actually look up, and the converter above for everything in between. Both are computed from the same factor at full precision, so the table and the converter can never disagree — there is no second, rounded copy of the data anywhere on this page.
Frequently asked questions
Is the km to mi conversion exact?
Yes. 1 km = 1,000 m (exact) and 1 mi = 1,609.344 m (exact) are exact definitions, so the conversion is exact — results are rounded only for readability.
How do I convert km to mi in my head?
Multiply kilometers by 0.6 — 100 km/h is about 62 mph.
Why do other sites show slightly different km to mi results?
They round at different steps. This page computes with the full-precision factor and rounds only the final displayed number, so small trailing digits can differ from sites that round earlier.