Hectares to Acres Converter — ha to ac
Convert any number of hectares to acres, square meters, square kilometers, square feet, square miles and square yards using the exact international conversion factor. One hectare equals exactly 2.47105381 acres.
ha
1 hectare = 2.47105381 acres (exact via the international foot)
1 ha = 10 000 m²; 1 acre = 4046.8564224 m² (exact definition)
Divide to find the factor: 10 000 ÷ 4046.8564224
Multiply your hectare value by the conversion factor
- 1
Conversion factor
10 000 ÷ 4 046.8564224 = 2.471053811 ha = 10 000 m²; 1 acre = 4 046.8564224 m² (exact via the international foot) - 2
Acres
1 × 2.47105381 = 2.47105
How does this calculator work?
Acres = hectares × 2.47105381. The factor comes from: 1 ha = 10 000 m² and 1 acre = 4046.8564224 m² (43 560 sq ft × 0.09290304 m²/sq ft). Rule of thumb: 1 ha ≈ 2.5 acres; 1 acre ≈ 0.4 ha. The conversion is exact through the internationally defined foot (0.3048 m exactly).
Formula
How this is calculated
The hectare (ha) is the standard SI-derived unit for land area, equal to exactly 10 000 square meters — a square 100 m on each side. It is the unit used internationally in cadastral mapping, agriculture, and forestry. The acre is the customary land-area unit in the United States, United Kingdom, and some Commonwealth countries, historically defined as the area a yoke of oxen could plough in a day, and later standardised as 43 560 square feet.
The conversion is exact through the international yard. The international yard is defined as exactly 0.9144 m, making 1 foot = 0.3048 m and 1 square foot = 0.09290304 m². One acre of 43 560 sq ft therefore equals 43 560 × 0.09290304 = 4046.8564224 m². Dividing the hectare (10 000 m²) by this gives the factor 10 000 / 4046.8564224 = 2.47105381 acres per hectare — the exact, internationally agreed value.
For mental estimation: roughly 2.5 acres ≈ 1 hectare, or 1 acre ≈ 0.4 ha. The calculator also outputs square feet (useful for US real estate) and square miles (large parcels). Note that US survey measurements historically used a slightly different foot (1200/3937 m instead of 0.3048 m), producing a US survey acre about 4 parts per million larger than the international acre — a negligible difference for all practical purposes.
Frequently asked questions
One hectare equals exactly 2.47105381 acres. Rounded to four decimal places: 2.4711 ac. Conversely, 1 acre equals approximately 0.40469 ha (or exactly 0.40468564224 ha).
Yes — 1 ha ≈ 2.47 acres, so "about 2.5 acres" is correct to within 1.2%. For rough fieldwork or conversational estimates this works well. For legal land transfers or planning applications, always use the full conversion factor 2.47105381.
Exactly 100 hectares = 1 km² (since 1 km² = 1 000 000 m² and 1 ha = 10 000 m²). Equivalently, 1 km² ≈ 247.1 acres. A US section (1 square mile) ≈ 640 acres ≈ 259 hectares.
Also known as
TG we-Calculate Editorial Team. (2026). Hectares to Acres Converter — ha to ac [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/hectares-to-acres-converter
TG we-Calculate Editorial Team. "Hectares to Acres Converter — ha to ac." TG we-Calculate. 2026. https://we-calculate.com/calculator/hectares-to-acres-converter.
TG we-Calculate Editorial Team, "Hectares to Acres Converter — ha to ac," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/hectares-to-acres-converter
@misc{wecalculate_hectares_to_acres_converter, title = {Hectares to Acres Converter — ha to ac}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/hectares-to-acres-converter}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?