# Kilometers to miles converter

> Convert kilometers to miles (km to miles) with the exact factor, a conversion chart and worked steps.

Interactive version: https://www.calcopenly.com/conversion/km-to-miles
Subject: Unit converters

Kilometer distances are common on road signs and running routes. Convert the total route length before estimating travel time; distance alone does not include traffic, stops or elevation. Race names may be rounded labels, so use the measured distance when precision matters.

One kilometre is about 0.6213711922 miles, so 10 km is 6.213712 mi. To convert km to miles, multiply by 0.6213711922; to convert back, multiply by 1.609344.

The international mile is exactly 1,609.344 m, which is 5,280 feet. The factor has no exact decimal form, so results are computed with 50 significant digits and rounded only for display.

## Inputs

- **Kilometers (km)**

## Results

- Miles (mi) — main result
- Conversion
- 1 mi in kilometers (km)

## Formula

$$
\text{miles} = \text{kilometers} \times 0.621371192237
$$

## Worked examples

### 10 km to mi

- Kilometers (km): 10 km
- **Miles: 6.2137119224 mi**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 100 km to mi

- Kilometers (km): 100 km
- **Miles: 62.1371192237 mi**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 1 km to mi

- Kilometers (km): 1 km
- **Miles: 0.6213711922 mi**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

## Questions

### When would I convert km to miles?

Kilometer distances are common on road signs and running routes. Convert the total route length before estimating travel time; distance alone does not include traffic, stops or elevation. Race names may be rounded labels, so use the measured distance when precision matters.

### How many miles are in a kilometre?

One kilometre is about 0.6213711922 miles. The international mile is exactly 1,609.344 m, which is 5,280 feet.

### How do you convert km to miles?

Multiply the number of kilometers by 0.6213711922. For example, 10 km × 0.6213711922 = 6.213712 mi. To go the other way, divide by 0.6213711922.

### How can I estimate km to miles without a calculator?

Multiply by 0.62. That is 0.2% low of the exact factor 0.6213711922, so 10 km comes out as 6.2 mi instead of 6.2137.

### How accurate is the kilometers to miles converter?

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 3 worked examples whose answers come from independent sources; for example, “10 km to mi” is checked against Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions).

### Where does the method come from?

NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B; NIST Handbook 44, Appendix C: General tables of units of measurement; BIPM, The International System of Units (SI Brochure), 9th edition.

## Sources

- [NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C: General tables of units of measurement](https://www.nist.gov/pml/weights-and-measures/publications/nist-handbooks/handbook-44)
- [BIPM, The International System of Units (SI Brochure), 9th edition](https://www.bipm.org/en/publications/si-brochure)