Converter Tools

Length Converter

Convert length and distance between millimetres, centimetres, metres, kilometres, inches, feet, yards, miles and nautical miles. Accurate, instant and fully offline.

Runs entirely in your browser — nothing you type is uploaded.

This tool runs in your browser. Please enable JavaScript to use it — the guide below explains what it does.

Note: the converter runs in your browser with JavaScript. With JavaScript off you can read this guide, but the controls will not appear.

Convert length and distance instantly

This tool converts between common length and distance units entirely in your browser. Enter an amount, pick the units to convert from and to, and get an accurate result — with a Swap button to flip the direction and a Copy button for the result.

How it works

  1. Enter an amount (decimals and negative values are allowed).
  2. Choose the From and To units from the dropdowns.
  3. Click Convert to see the result, or use Swap to reverse the direction.
  4. Copy the result or Reset to start again.

Supported units & reference factors

  • Metric — millimetre, centimetre, metre, kilometre.
  • Imperial / US — inch (0.0254 m), foot (0.3048 m), yard (0.9144 m), mile (1609.344 m).
  • Nautical — nautical mile (1852 m).
  • Base unit — every value is converted through metres for accuracy.

Examples

  • 1 kilometre = 1000 metres = 0.621371 miles
  • 1 inch = 2.54 centimetres; 1 foot = 12 inches
  • 1 mile = 1.609344 kilometres; 1 nautical mile = 1.852 kilometres

Accuracy & formatting

Conversions use exact defined factors and are formatted cleanly, so you won't see noise like 1.0000000000000002 — just a precise, readable value. Meaningful precision is kept; results are not over-rounded.

Privacy

Everything runs locally in your browser. The values you enter are never uploaded, stored or shared, and the tool makes no network requests.

Frequently Asked Questions

Which length units are supported?
Millimetre, centimetre, metre, kilometre, inch, foot, yard, mile and nautical mile. You can convert from any of these to any other.
How accurate are the conversions?
It uses exact internationally defined factors — for example 1 inch = 0.0254 m, 1 mile = 1609.344 m and 1 nautical mile = 1852 m — converting your value through metres as a base unit. Results are formatted cleanly without introducing floating-point noise.
Can I convert decimals or negative values?
Yes. Decimals are fully supported, zero is allowed, and negative values are converted mathematically. Invalid, non-numeric, NaN or infinite inputs are rejected with a clear message.
Can I swap the units quickly?
Yes. The Swap button exchanges the From and To units and re-runs the conversion, so you can flip the direction in one click.
Is my data stored or sent anywhere?
No. All conversions run locally in your browser — the values you enter are never uploaded, saved or shared, and the tool makes no network requests.

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