Area conversion uses squared length definitions
CalcOS relates each area unit to the square meter. Metric square units follow exact powers of ten; customary square units are calculated by squaring their exact international length definitions.
A linear factor cannot be reused unchanged. Since one foot is 0.3048 meter, one square foot is 0.3048 × 0.3048 square meter.
Common area definitions
| Unit | Exact relationship | Common context |
|---|---|---|
| square foot | 0.09290304 m² | floor and property area |
| square yard | 0.83612736 m² | flooring and landscaping |
| acre | 4,046.8564224 m² | land area |
| hectare | 10,000 m² | metric land area |
| square kilometer | 1,000,000 m² | large geographic area |
Acres and hectares
Acres belong to customary land measurement, while hectares are accepted for use with SI and equal exactly 10,000 square meters. Neither describes a fixed shape; both describe area only.
International versus survey foot
CalcOS uses the international foot, exactly 0.3048 meter. Historical U.S. surveying records may use the former survey-foot definition and require explicit legacy treatment.
Popular area converters
Authoritative references: BIPM SI Brochure and NIST Handbook 44, Appendix C.