Convert km to mi

km
0.621371192237mi

1 km = 0.621371192237 mi

Type a value in kilometres and the answer in miles appears as you go. The conversion is exactly 0.621371192237 mi to the kilometre, and it happens on your own machine — this page asks nothing of a server once it has loaded.

  • Where it runs

    In your browser. The number you type is never part of a request.

  • Exact by definition

    1 km is exactly 0.621371192237 mi — a definition, not a rounded factor.

  • Answers as you type

    No button, no wait. The worked answer is already on the page before any script runs.

Kilometre and Mile

Kilometres are the road distance nearly everywhere outside the United States and the United Kingdom, which is why converting them is usually about reading a map or a race entry.

A mile is 1,760 yards — a number that comes from a Roman thousand paces, adjusted by an Elizabethan statute to fit the furlong. It is exactly 1,609.344 metres.

kilometres to miles in practice

  • 50.45 km is 31.35 mi

    — the Channel Tunnel.

  • 384400 km is 238900 mi

    — the average distance to the Moon.

kilometres to miles at a glance

kmmi
10.621371192237
21.24274238447
31.86411357671
53.10685596119
106.21371192237
2012.4274238447
5031.0685596119
10062.1371192237

Every figure here is computed from the same definition the calculator uses, so the table cannot drift away from the answer above it.

Convert km to mi: common questions

How many miles are in a kilometre?

Exactly 0.621371192237. One kilometre is 0.621371192237 miles, and the box above will do it for any figure you type.

Is this conversion exact, or rounded?

The ratio is exact. It is not a rounded constant typed into a table: it is derived from the definitions of the two units, so it agrees with any other correct converter to as many digits as you care to compare.

Why does another converter show a slightly different number?

Almost always rounding rather than disagreement. Many converters cut the answer to two or four decimals, and some carry a factor that was rounded before the multiplication rather than after. The figures here are computed from the exact definitions and only rounded on the way to the screen.

Where these figures come from

The claims this page makes about length units are checkable, and these are the documents that settle them.

How this page works

The factor is a constant in the page and the arithmetic is four operations, so nothing is sent anywhere and nothing needs to be. The number you type never leaves the browser — there is no request for it to travel in.

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