Kilometers vs Miles: What's the Difference?

Kilometers and miles are the world's two most common distance units — understanding both is essential for international travel.

Kilometers and miles are the two most common units for measuring distance. This guide explains the difference, how to convert between them, and which countries use which system.

The Metric System: Kilometers

The kilometer (km) is part of the metric system, used by the vast majority of countries worldwide. One kilometer equals 1,000 meters.

The Imperial System: Miles

The mile is used primarily in the United States, United Kingdom, and a few other countries. One mile equals approximately 1.609 kilometers.

How to Convert

Kilometers to miles: multiply by 0.6214
Miles to kilometers: multiply by 1.609

Quick mental math: to roughly convert km to miles, multiply by 6 and divide by 10. When using SnapDistance, results are displayed in both units automatically.

Nautical miles — used in maritime and aviation — correspond to one minute of latitude, making them practical for chart-based navigation.

Nautical Miles

One nautical mile equals 1.852 km (1.151 miles) and corresponds to one minute of latitude, making it useful for navigation.

Which Countries Use Which System?

Only three countries have not officially adopted the metric system: the United States, Myanmar, and Liberia. The UK uses a mix.

Common Conversion Reference

1 km = 0.621 miles — about the distance of a 10-minute drive
10 km = 6.2 miles
100 km = 62.1 miles
344 km = 214 miles — London to Paris
1,000 km = 621.4 miles
3,944 km = 2,451 miles — New York to Los Angeles
5,570 km = 3,461 miles — New York to London

Try It With Real Routes

See km and miles side by side on actual routes:

Tokyo to Osaka — 397 km (247 mi)
Sydney to Melbourne — 714 km (444 mi)
Dubai to Singapore — 5,844 km (3,631 mi)

Or explore distances by region: US distances, UK distances, or Japan distances.

Frequently Asked Questions

Which unit is more accurate?

Both are equally accurate — they are different scales for the same measurement.

Why does the US still use miles?

Cultural inertia and the cost of changing infrastructure have kept miles in use since a voluntary metric conversion effort in the 1970s.

How do I know if a distance is in km or miles?

Check the source. Tools like SnapDistance display both to avoid confusion.

What is a nautical mile used for?

Aviation and maritime navigation, because they correspond directly to degrees of latitude.