Km to Miles Converter

About Km → Miles

Kilometers measure road signs and race distances in most countries; miles dominate US odometers and UK/US road culture. Converting km to miles helps interpret GPS routes abroad.

One kilometer equals about 0.621371 miles—multiply km by that factor for miles.

Use this page when your known value is in kilometers and you need miles.

How to use this tool

Enter distance in kilometers. Calculate to see miles.

Formula & methodology

This km to miles converter applies the standard relationship below. Intermediate values are kept at full precision; only the displayed result is rounded.

miles = km x 0.621371192

Worked example

A 10 km race: 10 × 0.621371 = 6.21 miles. Going back, 6.2137 ÷ 0.621371 = 10 km. A quick mental check is that 8 km is almost exactly 5 miles.

Tips for accurate results

• Marathon is 42.195 km or about 26.219 miles.
• Speed limits in km/h convert separately—see kmh-to-mph.
• For mental math, 5 km is roughly 3.1 mi.
• Need miles to km? Use the miles-to-km tool instead.

Frequently asked questions

Sources & references

The factors and formulas used by this tool follow these references:

• NIST Special Publication 811 — Guide for the Use of the International System of Units (SI)
• BIPM — The International System of Units (SI Brochure, 9th edition)

Last reviewed: September 2026. Found an error? Tell us and we will correct it.