How many length units do you support?
We support 27 length units spanning metric (meter, kilometer, centimeter, millimeter, micrometer, nanometer, picometer), imperial (inch, foot, yard, mile), maritime (nautical mile, fathom), astronomical (light-year, astronomical unit, parsec), and historical (league, hand, link, rod, chain, furlong, span, cubit, finger, palm, ell).
Are the conversions accurate?
Yes. Every conversion uses internationally recognized conversion factors. For example, 1 inch = exactly 2.54 centimeters, 1 mile = exactly 1.609344 kilometers. Results are computed with full floating-point precision.
How do I convert between metric and imperial?
Simply select your source unit (e.g., Meter) and target unit (e.g., Foot) using the converter widget above, or click any unit card to see all its conversion options. Our most popular cross-system conversions include meter↔foot, kilometer↔mile, and centimeter↔inch.
What are the historical/obscure units like cubit and fathom?
These are traditional measurement units used historically. A cubit (~45.72 cm) is based on forearm length, used in ancient Egypt and biblical texts. A fathom (1.8288 m) measures water depth. A furlong (201.17 m) is still used in horse racing. We include these for research, education, and historical reference.
Can I convert astronomical distances like light-years?
Yes. We support light-year (~9.461 trillion km), astronomical unit (~149.6 million km), and parsec (~3.26 light-years). These are used in astronomy to measure distances between stars and galaxies.
Is this tool free to use?
100% free with no limits. No sign-up, no premium tiers, and no ads-before-results. All 729 conversion pages are completely free to use.