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Length converter

Unit converters

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

Updated

Convert length

In every unit

UnitValueCopy
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.

  1. Step 1
    Type the value

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

  2. 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.

  3. 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

UnitSymbolIn metres
Nanometrenm0.000 000 001
Micrometreµm0.000 001
Millimetremm0.001
Centimetrecm0.01
Metrem1
Kilometrekm1 000
Inchin0.025 4
Footft0.304 8
Yardyd0.914 4
Milemi1 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.

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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