Length Converter

Move between common metric and imperial length units with an explicit conversion factor.

Free to useCalculated in your browserv0.2.1 · Method documented September 12, 2026

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Know the limits. Uses international units, not historical survey units. Values are displayed with up to eight decimal places; very small values use scientific notation.

How it works

For example, 1 international inch is 25.4 mm and 1 foot is 0.3048 m. The calculator routes all conversions through meters.

Result = input × meters per source unit ÷ meters per destination unit

Try the example

The starter inputs above produce:

Converted length: 25.4 mm

Change the inputs to match your own situation. The result is an estimate or text transformation, not a substitute for reviewing your source data.

A few useful details

How do I enter 3/8 inch?

Enter its decimal form, 0.375, and select inches. The result in millimeters is 9.525.

Are feet and inches entered together?

No. Convert mixed feet-and-inches measurements into a single unit before entering them.

Do I need an account?

No. This release runs without an account, API key or payment. Saving a favorite stores only the tool’s identifier in this browser, not your inputs.