km to miles converter
1 kilometer is 0.621371 miles. To convert km to miles, divide the kilometers by 1.609344 or multiply by 0.621371.
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10 kilometers =
6.21371mi
Formula: mi = km ÷ 1.609344
Show the steps
- Definition: 1 km = 1000 m (SI prefix kilo); 1 mi = 1609.344 m exactly (5280 ft)
- 10 km ÷ 1.609344 = 6.21371 mi
Definitions used: 1 km = 1000 m (SI prefix kilo); 1 mi = 1609.344 m exactly (5280 ft).
Source: NIST SP 811, Appendix B.8, checked on .
How to convert kilometers to miles
Divide the value in kilometers by 1.609344. The factor follows from the definitions: 1 km = 1000 m (SI prefix kilo), and 1 mi = 1609.344 m exactly (5280 ft).
mi = km ÷ 1.609344
Worked example: 10 km to mi
- Definition: 1 km = 1000 m (SI prefix kilo); 1 mi = 1609.344 m exactly (5280 ft)
- 10 km ÷ 1.609344 = 6.21371 mi
- Answer: 10 km = 6.21371 mi.
Kilometers to miles chart
| Kilometers (km) | Miles (mi) |
|---|---|
| 1 | 0.621371 |
| 2 | 1.24274 |
| 3 | 1.86411 |
| 5 | 3.10686 |
| 8 | 4.97097 |
| 10 | 6.21371 |
| 15 | 9.32057 |
| 20 | 12.4274 |
| 21.0975 | 13.1094 |
| 25 | 15.5343 |
| Kilometers (km) | Miles (mi) |
|---|---|
| 30 | 18.6411 |
| 40 | 24.8548 |
| 42.195 | 26.2188 |
| 50 | 31.0686 |
| 80 | 49.7097 |
| 100 | 62.1371 |
| 160 | 99.4194 |
| 200 | 124.274 |
| 500 | 310.686 |
| 1,000 | 621.371 |
Values rounded to 6 significant digits. Type any other number in the converter at the top of the page.
How many miles is a 5K, a 10K and a marathon?
A 5K is 3.107 miles and a 10K is 6.214 miles. A half marathon (21.0975 km) is 13.11 miles and a marathon (42.195 km) is 26.22 miles.
How do you convert km to miles without a calculator?
Multiply by 5 and divide by 8. 80 km × 5 ÷ 8 = 50 miles; the exact value is 49.71 miles. A rougher rule is “take 60%”: 100 km is about 60 miles (exactly 62.14).
More questions about kilometers and miles
How many miles is 1 km?
1 km is 0.621371 miles, a little under two thirds of a mile.
Which is longer, a kilometer or a mile?
A mile. One mile is exactly 1.609344 km, so it is about 61% longer than a kilometer.
How many miles is 100 km?
100 km is 62.1371 miles.
Is this the statute mile or the nautical mile?
The statute (land) mile of 5,280 feet. A nautical mile is 1.852 km, used at sea and in aviation; you can convert it on the length page.
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Sources and limits
- NIST SP 811, Appendix B.8
NIST Special Publication 811, Guide for the Use of the SI, Appendix B.8: Factors for Units Listed Alphabetically (page updated August 18, 2025).
National Institute of Standards and Technology. Edition or effective date: . Text in force when checked on .
This is a calculation aid, not an official measurement service. Results are rounded to 6 significant digits for display. For trade, engineering, medical dosing or legal documents, confirm the figure in the official source. Nothing you type leaves your browser.