Length Converter — Free
Runs 100% in your browser — your files never leave your device.
A tape measure speaks inches, a map speaks kilometers, and a machining drawing speaks millimeters. Type a value into any of the ten fields and every other unit fills in instantly, from nanometers to miles, using exact defined factors.
How it works
- 1
Pick your starting unit
Any of the ten rows can be the source — metric or imperial.
- 2
Type the value
All nine other units update on the same keystroke.
- 3
Read or copy the answer
Results keep twelve significant digits of precision.
About this tool
The exact definitions behind the numbers
Since 1959 the inch is defined as exactly 2.54 centimeters, which pins the foot (12 inches), the yard (3 feet), and the mile (5,280 feet) to exact metric values. Metric prefixes are powers of ten by definition. That means every conversion here is exact — not an approximation that drifts with use. For square measure, use the area converter.
When the small units matter
Nanometers size microchips and wavelengths of light; micrometers size cells and fabric threads; millimeters and centimeters rule hardware and maps. Knowing that a human hair is about 70 micrometers wide turns those tiny exponents into things you can picture.
Frequently asked questions
How many inches are in a meter?
Exactly 39.3700787… — a meter is 100 divided by the exact 2.54 cm per inch. For quick estimates, a meter is roughly a yard and a bit more.
What is the difference between a nautical mile and a regular mile?
A nautical mile is exactly 1,852 meters — longer than the 1,609.344-meter land mile — and it is tied to latitude, which is why sea and air navigation use it. Speeds in knots live on the speed converter.
Is a nanometer smaller than a micrometer?
Yes, a thousand times smaller. One micrometer equals one thousand nanometers; a nanometer is roughly the width of four or five atoms in a row.