Area converter
Convert area between metric and imperial units.
Fill in the fields and the result will appear here automatically.
Converts area between square millimetres, centimetres, metres and kilometres, hectares, square inches and feet, and acres. Unit definitions specify the factors; calculation and display have finite precision.
How it works
Formula and logic
Every unit has an exact factor to the square metre.
Example
A hectare is 10,000 m² and an acre is 4046.8564224 m².
Fields and units
- Area — in the selected source unit
- From unit — list option
- To unit — list option
How to use
- — Enter the value.
- — Pick the source unit.
- — Pick the target unit.
Method and limitations
- Calculation method
- Formula and logic
- Data or methodology source
- BIPM: SI Brochure, version 4.01 (2026) NIST: conversion-factor tables, Appendix B.9 NIST: international and historical US survey foot
- Limitation
- The result is a rounded unit conversion. Check the entered value and selected units.
FAQ
How is a hectare different from an acre?
A hectare is exactly 10,000 m² while an acre is 4046.86 m². One hectare is about 2.47 acres.
Why are the factors not squares of length factors?
They are, but written out as finished numbers so the converter does not depend on dimensional analysis and stays easy to verify.
Is it suitable for land plots?
Yes, hectares and acres are standard land measures. For documents, check against the official survey.
Are the imperial area units exact?
Yes. A square inch is 0.00064516 m² by the definition of the inch.