Updated October 9, 2026
Length Converter
Convert between millimeters, centimeters, meters, kilometers, inches, feet, yards, miles and nautical miles. Type an amount, pick the units, get the answer instantly.
How the conversion works
Every unit is defined as an exact number of meters: 1 inch is 0.0254 m exactly, 1 foot is 0.3048 m exactly, 1 mile is 1609.344 m exactly. To convert, the tool changes your amount into meters first, then into the target unit, so every pair converts through one consistent path.
Worked example
Convert 5 miles to kilometers: 5 × 1609.344 = 8046.72 meters, then 8046.72 ÷ 1000 = 8.04672 km.
A note on precision
Results show up to 8 significant digits, more than enough for everyday use. For surveying or engineering, remember that real-world measurements carry their own uncertainty far larger than any rounding here.
Planning estimate only. Results use the list prices shown and may differ from your actual bill. Terms
Frequently asked questions
How many centimeters are in an inch?
2.54 cm, exactly. The inch has been defined as exactly 25.4 millimeters since the 1959 international yard and pound agreement.
What is a nautical mile?
1,852 meters exactly. It was originally one minute of latitude and is still the standard unit for sea and air navigation.
Why is a mile 1.609344 kilometers?
It is the exact international definition: 1 yard = 0.9144 m, 1 mile = 1,760 yards, so 1 mile = 1,760 × 0.9144 = 1,609.344 m.
How precise are the results?
Up to 8 significant digits, using exact defined factors rather than rounded ones. That is plenty for cooking, travel, DIY and schoolwork.