Length Converter

Convert between 40+ length units instantly. Keyboard friendly and accessible.

Crafted by Arifur Rahman

Precision

How does the length converter work?

  • Choose a source unit from the dropdown or tap a popular conversion chip.
  • Enter a value—results update automatically with a 150 ms debounce.
  • Swap the direction with the central button to reverse units instantly.
  • Adjust precision with Auto significant figures or Fixed decimal settings.
  • Copy formatted results or inspect unit definitions via the info tooltip.

What makes this length converter different?

Popular units first

Meter, centimeter, inch, foot, and mile stay pinned to the top for quick selection.

Science & astronomy ready

Convert angström, astronomical unit, light-second, parsec, and more with exact constants.

Accessibility built in

Keyboard-driven dropdowns, live announcements, and visible focus rings meet WCAG-AA.

Console API hook

Use window.convert(value, from, to) to test calculations right inside your browser.

How can I control rounding?

The converter offers two precision modes:

Auto mode
Adapts between three and eight significant figures and switches to scientific notation for extreme magnitudes.
Fixed mode
Choose exact decimal places from 0–12 to align with engineering or compliance requirements.

Both inputs respect your last-edited field, so you can evaluate conversions in either direction without losing context.

Which conversion services are covered?

  • Metric ↔ Imperial: centimeter, meter, kilometer, inch, foot, yard, mile.
  • Scientific units: micrometer, nanometer, angström for lab workflows.
  • Nautical distances: nautical mile with 1852 m exact and reverse lookups.
  • Astronomy scale: astronomical unit, light-second, light-year, and parsec.
  • Console-ready API: Pair with automation scripts using the exposed conversion function.

Unit references

  • International foot is exactly 0.3048 m; the U.S. survey foot was retired in 2023.
  • Nautical mile = 1852 m exactly; cable length (international) = 185.2 m (1/10 nmi).
  • Angström, point, pica, astronomical unit, light-year, and parsec follow current international definitions.

Length Converter FAQs

Which length units are supported?

The converter includes all SI prefixes, internationally agreed inch–mile standards, nautical miles, and science-grade units like angström, astronomical unit, and parsec.

How do I convert between metric and imperial units quickly?

Use the popular chips such as cm → in or m → ft, or select units manually from the dropdown which keeps metric and imperial favorites at the top.

Can I tune rounding and significant figures?

Yes—Auto mode adjusts significant figures intelligently, while Fixed mode lets you lock in 0–12 decimal places for compliance or reporting.

Does it handle astronomy and scientific distances?

Absolutely. Convert astronomical unit, light-second, light-year, and parsec using precise constants referenced from international standards.

Is there a way to integrate results into scripts?

Open the browser console and call window.convert(value, fromKey, toKey) or window.convertFraction for BigInt-based precision.