Length converter

Unit converters

Convert m, ft, in, mi, km and more with precision.

Updated May 31, 2026

Convert length

ValueUnit

In every unit

Unit	Value	Copy
Nanometre nm	999,999,999.9999999
Micrometre µm	1,000,000
Millimetre mm	1,000
Centimetre cm	100
Metre m	1
Kilometre km	0.001
Inch in	39.37007874
Foot ft	3.2808399
Yard yd	1.0936133
Mile mi	0.00062137

Quick start

How to convert length

Type a value, pick the source unit, copy the result from any row.

Step 1

Type the value

Enter your measurement and pick its unit. Switching units converts the displayed value so the meaning is preserved.
Step 2

Read every unit

All ten units — nm, µm, mm, cm, m, km, in, ft, yd, mi — update live. The source unit is highlighted.
Step 3

Copy a row

Hit Copy on any row to grab that unit's value. Extremely small or large numbers switch to scientific notation automatically.

In-depth guide

Length converter — metric and imperial in one table

Convert between ten common length units — from nanometres to miles — in a single table. Type a value, pick the source unit, and every other unit updates live.

Supported units

Unit	Symbol	In metres
Nanometre	nm	0.000 000 001
Micrometre	µm	0.000 001
Millimetre	mm	0.001
Centimetre	cm	0.01
Metre	m	1
Kilometre	km	1 000
Inch	in	0.025 4
Foot	ft	0.304 8
Yard	yd	0.914 4
Mile	mi	1 609.344

Conversions worth memorising

1 inch = 2.54 cm (exact)
1 foot = 30.48 cm
1 metre ≈ 3.281 feet
1 mile = 1.609344 km (exact)
1 km ≈ 0.6214 mile
1 yard = 0.9144 m (exact)

Typical use cases

Travel — read US road signs in km, see European weather forecasts in metres.
Furniture & DIY — translate imperial drawings to mm for European fittings.
Engineering — verify spec sheet conversions before machining.
Science — micrometres, nanometres for cell biology, optics and electronics.
Apparel — convert inseam and chest measurements between regional sizing.

Converting length without slips

When to reach for it. Use it to move between metric and imperial length units for everyday measuring, DIY and travel.

When something else is better. For surveying, machining or legal land records, use the controlled standard your domain mandates rather than a quick web convert.

The pitfall to watch. Confusing similar labels (statute mile vs nautical mile, US vs imperial units) is the classic source of a wrong answer.

Everything runs on your device. The values you enter are processed locally in this browser tab — EpitomeTool does not send your input to a server, store it, or log it. That means you can use the tool offline once the page has loaded, and refreshing the tab wipes the slate.

Frequently asked questions

Which conversion factors are used?

International yard and pound agreement (1959) — 1 inch = 25.4 mm exactly, 1 foot = 304.8 mm, 1 yard = 914.4 mm, 1 mile = 1609.344 m. SI units use their exact decimal relationships.

Why are some values shown in scientific notation?

When a result is very small (< 0.0001) or very large (≥ 10^15), we switch to exponential form so the magnitude stays readable. The underlying number is unaffected.

Is the data accurate to enough decimal places?

Yes for engineering — we keep up to 8 significant digits. For metrology or scientific work where parts-per-million matters, use a dedicated tool that does interval arithmetic.

Does the converter work offline?

Yes. Everything runs in your browser. No request leaves the page during conversion.

What's the difference between a foot and a survey foot?

Tiny — the US survey foot was officially deprecated at the end of 2022. This tool uses the international foot (0.3048 m exactly), which matches every modern engineering standard.

Can I add a custom unit?

Not yet. The supported units cover everyday and engineering needs. If you have a strong use case (e.g. astronomical units, parsecs), open a feature request.

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