# Length Converter

> Convert length between 14 units with the formula, a reverse conversion and a quick-reference table.

To convert length, enter a value and pick the units. The result appears instantly with the exact conversion formula, the reverse conversion, a quick-reference table of common values and every one of the 14 supported units. The inch is defined as exactly 25.4 mm and the mile as exactly 1609.344 m, so metric–imperial length conversions are exact rather than approximate.

**URL:** https://convertto.tech/t/length-converter
**Category:** Unit Converters (https://convertto.tech/c/unit-converters)
**Privacy:** Runs entirely in the browser; no upload
**Cost:** Free, no sign-up
**Last updated:** 2026-08-01

## Key facts

- **Units supported:** 14
- **Base unit:** m
- **Precision:** Adjustable from 1 to 15 significant figures
- **Shows:** Formula, reverse conversion and a common-values table
- **Privacy:** Runs entirely in your browser — nothing is uploaded
- **Cost:** Free, unlimited, no sign-up

## How to use

1. Set the value.
2. Choose the from.
3. Choose the to.
4. Turn "Swap direction" on or off as needed.
5. Set the significant figures.
6. The result appears immediately — copy or download it.

## FAQ

### How accurate is this length converter?

Conversions use exact SI definitions where one exists and are computed in double-precision floating point. You can raise the displayed precision to 15 significant figures, and the unrounded result is shown separately. The inch is defined as exactly 25.4 mm and the mile as exactly 1609.344 m, so metric–imperial length conversions are exact rather than approximate.

### Can I reverse the conversion without retyping?

Yes — the swap toggle reverses the two units in place. The reverse rate is also shown in the detail section, so you can read it either way without changing anything.

### Is my data sent anywhere?

No. The conversion is plain JavaScript running in your browser. No value you type is transmitted, logged or stored.

### Can I link to a specific conversion?

Yes. The URL updates as you type, so you can bookmark or share a link that reopens with exactly the same conversion.

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