# Miles to kilometers converter

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

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

A route listed in miles may need a metric distance for a map, training log or reimbursement form. This converter uses the international land mile. Nautical miles describe a different distance and need their own conversion rather than a change in rounding.

One mile is exactly 1.609344 kilometers, so 26.2 mi is 42.164813 km. To convert miles to km, multiply by 1.609344; to convert back, multiply by 0.6213711922.

The international mile is exactly 1,609.344 m, which is 5,280 feet. Because both units are defined exactly, the factor above is exact and the results here carry no conversion error.

## Inputs

- **Miles (mi)**

## Results

- Kilometers (km) — main result
- Conversion
- 1 km in miles (mi)

## Formula

$$
\text{kilometers} = \text{miles} \times 1.609344
$$

## Worked examples

### 26.2 mi to km

- Miles (mi): 26.2 mi
- **Kilometers: 42.1648128 km**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 3.1 mi to km

- Miles (mi): 3.1 mi
- **Kilometers: 4.9889664 km**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 50 mi to km

- Miles (mi): 50 mi
- **Kilometers: 80.4672 km**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

## Questions

### When would I convert miles to km?

A route listed in miles may need a metric distance for a map, training log or reimbursement form. This converter uses the international land mile. Nautical miles describe a different distance and need their own conversion rather than a change in rounding.

### How many kilometers are in a mile?

One mile is exactly 1.609344 kilometers. The international mile is exactly 1,609.344 m, which is 5,280 feet.

### How do you convert miles to km?

Multiply the number of miles by 1.609344. For example, 26.2 mi × 1.609344 = 42.164813 km. To go the other way, divide by 1.609344.

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

Multiply by 1.6. That is 0.6% low of the exact factor 1.609344, so 26.2 mi comes out as 41.92 km instead of 42.1648.

### How accurate is the miles to kilometers 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, “26.2 mi to km” 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)