Length converter
Switch between metric and imperial distances — millimeters through miles — with exact factors and an instant answer. Enter one value and see it across every length unit at once.
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How to convert length
Type the amount
Enter the distance you already have — decimals and negatives are fine.
Pick both units
Choose the unit you're starting from and the one you want. Hit swap to reverse them.
Grab the number
The result updates live, and the table lists the same distance in every other length unit.
Common length conversions
These are the equivalences most people look up, all built on the internationally fixed definition that one inch equals exactly 2.54 centimeters:
1 inch = 2.54 cm · 1 foot = 30.48 cm · 1 yard = 0.9144 m · 1 mile = 1.609344 km · 1 kilometer = 0.621371 mi · 1 meter = 3.28084 ft · 1 centimeter = 0.393701 in · 1 nautical mile = 1.852 km.
Metric or imperial?
Metric units scale by tens, so moving between millimeters, centimeters, meters and kilometers is just shifting a decimal point. Imperial units — inch, foot, yard, mile — use fixed but uneven steps, which is exactly where a converter earns its keep.
Nautical miles are different
A nautical mile (1,852 m) is longer than a land mile and is used in aviation and shipping because it maps neatly onto one minute of latitude. If you're measuring a road trip, you want the ordinary mile instead.
Length converter FAQ
Is one inch exactly 2.54 cm?
Yes. Since 1959 the inch has been defined as precisely 0.0254 meters, so all inch, foot, yard and mile conversions here are exact rather than approximate.
What's the quickest km-to-mile estimate?
Multiply kilometers by 0.62, or miles by 1.61. For a rough head-check, a 5 km run is about 3.1 miles. Convee gives you the precise figure.
Can I convert very small or very large lengths?
Yes — from nanometers to nautical miles. Extremely small or large results are shown in scientific notation so no precision is lost.
Does anything get uploaded?
No. The conversion runs entirely in your browser, so whatever you type stays on your device.