Which length units can I convert?
Metric: millimetres, centimetres, metres, and kilometres. Imperial/US: inches, feet, yards, and miles. Choose the unit you are entering; the other conversions appear as result tiles.
Interactive calculator loads when JavaScript is enabled. All calculations stay on your device.
Usage
- Convert DIY or sewing measurements between centimetres and inches.
- Translate road distances from kilometres to miles while travelling.
- Check product dimensions listed in mixed unit systems.
- Quick school homework checks for metric ↔ imperial length.
- Swap from any result tile to make that conversion your new starting point.
Knowledge
Length conversions use fixed factors relative to the metre. Common anchors: 1 in = 25.4 mm, 1 ft = 12 in, 1 yd = 3 ft, 1 mi = 1 609.344 m.
Metric steps are powers of ten (mm → cm → m → km). Enter one unit — the converter shows every other unit through metres behind the scenes.
FAQs
How accurate are the conversions?
Conversions use exact international factors (for example 1 in = 25.4 mm, 1 mi = 1 609.344 m). Display is rounded for readability.
Can I convert between metric and imperial?
Yes. Enter a value in any unit — for example metres — and read feet, miles, and the rest from the result tiles.
Can I swap from a result?
Yes. Tap Swap on any result tile to move that value and unit into the input and recalculate the other conversions.
Is my data stored or sent anywhere?
No. Everything runs in your browser. Nothing you type is uploaded or saved on a server.