From square meters (m²)
- Square meters to Square kilometersm² → km²
- Square meters to Hectaresm² → ha
- Square meters to Acresm² → ac
- Square meters to Square feetm² → ft²
Area conversion family
Area unit conversions
Area is a derived quantity representing the extent of a surface and has dimension L²; its coherent SI unit is the square meter (m²).
Five named units
Unit and factor reference
| Unit | Symbol | Factor to base | Relationship | Definition and variant |
|---|---|---|---|---|
| square meter | m² | 1 | defined | A square meter is the area of a square whose side length is one meter; it is the coherent SI unit for area. The base factor is exactly 1 by the family base-unit choice. |
| square kilometer | km² | 1000000 | exact | A square kilometer is (1 km)², so 1 km² = (1000 m)² = 1,000,000 m². The SI-prefix and squared-unit relationship is exact. |
| hectare | ha | 10000 | defined | A hectare is a non-SI decimal area unit used for land: 1 ha = 1 hm² = 10,000 m². Named variant: Land-area unit; not the SI prefix hecto used alone. The relationship to the square meter is exact. |
| acre | ac | 4046.8564224 | defined | An acre is 43,560 square international feet, which is exactly 4,046.8564224 m². Named variant: International-foot-based acre; legacy survey-foot-based acreage may use a different SI equivalent. The terminating base factor is exact for an acre based on the international foot. |
| square foot | ft² | 0.09290304 | defined | A square foot is the area of a square one international foot on each side: 1 ft² = (0.3048 m)² = 0.09290304 m² exactly. Named variant: International-foot-based square foot; not a square U.S. survey foot. The terminating base factor is exact for the international foot. |
Every ordered pair
All 20 area calculators
From square kilometers (km²)
- Square kilometers to Square meterskm² → m²
- Square kilometers to Hectareskm² → ha
- Square kilometers to Acreskm² → ac
- Square kilometers to Square feetkm² → ft²
From hectares (ha)
- Hectares to Square metersha → m²
- Hectares to Square kilometersha → km²
- Hectares to Acresha → ac
- Hectares to Square feetha → ft²
From acres (ac)
- Acres to Square metersac → m²
- Acres to Square kilometersac → km²
- Acres to Hectaresac → ha
- Acres to Square feetac → ft²
From square feet (ft²)
- Square feet to Square metersft² → m²
- Square feet to Square kilometersft² → km²
- Square feet to Hectaresft² → ha
- Square feet to Acresft² → ac
Evidence and review status
This family is machine-reviewed-pending-human. Automated checks verify structure, factor parity and source references; they do not constitute human or specialist approval.
Family assumptions and limits
- This family converts non-negative area magnitudes; it does not calculate area from dimensions or validate a parcel boundary.
- Acre and square foot are based on the international foot. Legacy survey-foot-derived areas are outside this family.
- The hectare is included as a non-SI decimal unit used for land area; it is exactly 10,000 m².
Authoritative references
- The International System of Units (SI), 9th edition, version 4.01; Bureau International des Poids et Mesures; Section 3, Table 7 (SI prefixes), p. 138; Section 4, Table 8, p. 140: 1 ha = 1 hm² = 10⁴ m².; accessed 2026-08-07
- NIST Handbook 44 (2026), Appendix C: General Tables of Units of Measurement; National Institute of Standards and Technology; Pages C-4, C-6, and C-11 to C-13; exact relationships 1 km² = 1,000,000 m², 1 ft² = 0.09290304 m², and 1 acre = 4,046.8564224 m².; accessed 2026-08-07