A square foot is exactly 0.09290304 square meters.
Square feet to Acres Converter — ft2 to ac
Convert Square foot (ft2) to Acre (ac) using the exact conversion factor (1 square foot = 0.0000229568 acre). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Square feet to Acres converter
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Convert acres, hectares, yield, seed, fertilizer, irrigation, and application-rate units.
Context values
Some unit families need one extra value for a physically accurate result.
An international acre is 4,046.8564224 square meters.
Result = input x 0.09290304 / 4046.856422.
Area units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Square feet to Acres
Square foot and Acre both measure a farming-related quantity — a land area or an application/yield rate per unit area — used to report crop yields, calculate how much fertilizer or seed a field needs, and plan irrigation. Square foot is typically associated with united States (real estate, construction), while Acre is typically associated with united States.
Formula
acres = square feet × 0.0000229568411387
This factor comes from each unit's defined relationship to the category's base unit: 1 square foot equals 0.09290304 base units, and 1 acre equals 4046.8564224 base units, so dividing one by the other gives the direct square foot-to-acre factor of 0.0000229568411387.
Simple example
1 ft2 × 0.00002295684114 = 0.0000229568 ac
1 square foot = 0.0000229568 acres.
Real-world example
100 ft2 × 0.00002295684114 = 0.0022956841 ac
100 square feet = 0.0022956841 acres.
Conversion table
| Square foot (ft2) | Acre (ac) |
|---|---|
| 1 ft2 | 0.0000229568 ac |
| 5 ft2 | 0.0001147842 ac |
| 10 ft2 | 0.0002295684 ac |
| 50 ft2 | 0.0011478421 ac |
| 100 ft2 | 0.0022956841 ac |
| 500 ft2 | 0.0114784206 ac |
Reverse conversion: Acre to Square foot
0.0000229568 ac × 43560 = 0.999998208 ft2
0.0000229568 acres = 0.999998208 square feet.
square feet = acres × 43560
For a page dedicated to this direction, see Acre to Square foot.
Square foot vs. Acre
| Aspect | Square foot | Acre |
|---|---|---|
| Family | US/imperial customary unit | US/imperial customary unit |
| Typical use | Real estate floor-space listings in the US | Measuring farmland, ranch, and rural property size in the US |
| Where it's used | United States (real estate, construction) | United States |
Understanding the Square foot
Square foot (ft2) measures area. A square foot is exactly 0.09290304 square meters, derived from the international foot fixed in 1959. It is classified as a US/imperial customary unit.
Where it's used: United States (real estate, construction) United Kingdom (some real estate and construction contexts)
Uses of the Square foot today
- Real estate floor-space listings in the US
- Construction, flooring, and materials estimation
- Rental and commercial property pricing
History of the Square foot
The square foot follows directly from the foot, standardized in England over centuries and fixed at exactly 0.3048 meters by the 1959 International Yard and Pound Agreement. Squaring that value gives the modern square foot.
Historical origin. Square foot was not the invention of a single named person; it developed through the process described above.
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.
Square foot — sources
- NIST — International yard and pound (1959) — Basis for the modern foot and its derived area unit.
Acre — sources
- NIST — US Survey Foot: Revised Unit Conversion Factors — Documents the 1959 international acre definition and the 2022/2023 survey-foot retirement.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many acres are in 1 square foot?
1 square foot equals 0.0000229568 acres, using the exact defined conversion factor rather than an estimate.
How do I convert square foot to acre?
Multiply the square foot value by 0.00002295684114. The converter above does this instantly to whatever precision you set.
How do I convert acre back to square foot?
Use the reverse factor: 1 acre equals 43,560 square feet. You can also use the swap control in the converter above to flip the direction instantly.
What is a square foot?
Square foot (ft2) measures area. A square foot is exactly 0.09290304 square meters, derived from the international foot fixed in 1959. It is classified as a US/imperial customary unit.
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.
Is the square foot to acre 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 square foot still used today?
United States (real estate, construction) United Kingdom (some real estate and construction contexts)