An international acre is 4,046.8564224 square meters.
Acres to Square Meters Converter — ac to m2
Convert Acre (ac) to Square Meter (m2) using the exact conversion factor (1 acre = 4,046.856422 square meter). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Acres to Square Meters converter
Converter
Area Converter
Convert land, construction, mapping, survey, and scientific area units.
Context values
Some unit families need one extra value for a physically accurate result.
Square metric area unit.
Result = input x 4046.856422 / 1.
Area uses the square meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Acres to Square Meters
Comparing Acre and Square Meter is common in agriculture and real estate, where US land is typically measured in acres and most of the rest of the world uses hectares. Acre is typically associated with united States, while Square Meter is typically associated with standard area unit worldwide except in US/UK contexts that favor square feet or acres.
Formula
square meters = acres × 4046.8564224
This factor comes from each unit's defined relationship to the category's base unit: 1 acre equals 4046.8564224 base units, and 1 square meter equals 1 base unit, so dividing one by the other gives the direct acre-to-square meter factor of 4046.8564224.
Simple example
1 ac × 4046.856422 = 4,046.856422 m2
1 acre = 4,046.856422 square meters.
Real-world example
10 ac × 4046.856422 = 40,468.56422 m2
10 acres = 40,468.56422 square meters.
Conversion table
| Acre (ac) | Square Meter (m2) |
|---|---|
| 1 ac | 4,046.856422 m2 |
| 5 ac | 20,234.28211 m2 |
| 10 ac | 40,468.56422 m2 |
| 25 ac | 101,171.4106 m2 |
| 50 ac | 202,342.8211 m2 |
| 100 ac | 404,685.6422 m2 |
Reverse conversion: Square Meter to Acre
1 m2 × 0.0002471053815 = 0.0002471054 ac
1 square meter = 0.0002471054 acres.
acres = square meters × 0.000247105381467
For a page dedicated to this direction, see Square Meter to Acre.
Acre vs. Square Meter
| Aspect | Acre | Square Meter |
|---|---|---|
| Family | US/imperial customary unit | SI derived unit |
| Typical use | Measuring farmland, ranch, and rural property size in the US | Real estate and floor-space measurement outside the US |
| Where it's used | United States | Standard area unit worldwide except in US/UK contexts that favor square feet or acres |
Understanding the Acre
Acre (ac) measures area. The international acre is defined as exactly 4,046.8564224 square meters. It is classified as a US/imperial customary unit.
Where it's used: United States United Kingdom (informal/historical, land registry legacy) Countries with historical British land-survey systems
International acre vs. US survey acre. The US survey acre, based on the US survey foot, differs from the international acre by about two parts per million. The US retired the survey foot/acre for federal use at the end of 2022.
Uses of the Acre today
- Measuring farmland, ranch, and rural property size in the US
- Real estate listings and zoning for land parcels
- Forestry and land-management reporting
History of the Acre
The acre originated in medieval England as a practical field measurement: the area a yoke of oxen could plow in one day, roughly a furlong (660 ft) long by a chain (66 ft) wide, giving the 43,560 square feet still used today.
Edward I's 1305 statute formalized this figure. In 1959, the same International Yard and Pound Agreement that fixed the pound also fixed the international acre at exactly 4,046.8564224 m², though the US separately retained a slightly different 'US survey acre' for some legacy land records until it was phased out in 2023.
Historical origin. Acre was not the invention of a single named person; it developed through the process described above.
Understanding the Square Meter
Square Meter (m2) measures area. The square meter is the SI derived unit of area: the area of a square with 1-meter sides. It is classified as a SI derived unit.
Where it's used: Standard area unit worldwide except in US/UK contexts that favor square feet or acres
Uses of the Square Meter today
- Real estate and floor-space measurement outside the US
- Construction and engineering area specifications
- Scientific and material-science measurements (e.g. material coverage, density per area)
History of the Square Meter
The square meter is a coherent SI derived unit — it isn't independently defined but follows automatically from the meter, the SI base unit of length, once the meter itself was fixed during the French metric reforms of the 1790s.
Historical origin. Square Meter was not the invention of a single named person; it developed through the process described above.
Acre — sources
- NIST — US Survey Foot: Revised Unit Conversion Factors — Documents the 1959 international acre definition and the 2022/2023 survey-foot retirement.
Square Meter — sources
- BIPM SI Brochure — Coherent derived units — Defines the square meter as the SI unit of area.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many square meters are in 1 acre?
1 acre equals 4,046.856422 square meters, using the exact defined conversion factor rather than an estimate.
How do I convert acre to square meter?
Multiply the acre value by 4046.856422. The converter above does this instantly to whatever precision you set.
How do I convert square meter back to acre?
Use the reverse factor: 1 square meter equals 0.0002471054 acres. You can also use the swap control in the converter above to flip the direction instantly.
What is a acre?
Acre (ac) measures area. The international acre is defined as exactly 4,046.8564224 square meters. It is classified as a US/imperial customary unit.
What is a square meter?
Square Meter (m2) measures area. The square meter is the SI derived unit of area: the area of a square with 1-meter sides. It is classified as a SI derived unit.
Is the acre to square meter conversion exact?
Yes. The international acre is defined as exactly 4,046.8564224 square meters. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between international acre vs. us survey acre?
The US survey acre, based on the US survey foot, differs from the international acre by about two parts per million. The US retired the survey foot/acre for federal use at the end of 2022.
Where is the acre still used today?
United States United Kingdom (informal/historical, land registry legacy) Countries with historical British land-survey systems