Square Feet to Acres Converter (ft² to ac)
43,560 ft² = 1 acre, so 1 ft² ≈ 0.0000229568 acre. Convert square feet to acres for lots, parking areas and site plans, with charts.
Acre (ac) = Square Foot (ft²) × 0.0000229568411387
Square Foot (ft²): A square foot is the area of a square one international foot on each side, exactly 0.09290304 m² or 144 square inches. Historical areas based on the US survey foot use a slightly different factor.
Acre (ac): The acre used here is 43,560 international square feet, exactly 4,046.8564224 m². Historical US survey acres are slightly larger, so check the foot definition when interpreting old survey records.
| Square Foot (ft²) | Acre (ac) |
|---|---|
| 1 | 0.0000229568411387 |
| 5 | 0.000114784205693 |
| 10 | 0.000229568411387 |
| 25 | 0.000573921028466 |
| 50 | 0.00114784205693 |
| 100 | 0.00229568411387 |
Building footprints, parking lots and lot sizes in many US zoning codes are measured in square feet, while land sales, farm records and tax maps often use acres. Dividing by 43,560 converts one to the other, because an acre is defined as exactly 43,560 ft². That makes a 10,890 ft² lot a quarter acre and a 5,000 ft² city lot a little under an eighth.
Small areas give small decimals: a 2,000 ft² house covers about 0.046 acre, so acreage becomes useful from a few thousand square feet up. When a listing gives a lot of "0.17 acre", that is about 7,400 ft², and rounding to two decimals can hide up to about 218 ft² either way, so ask for the surveyed square footage if the exact size matters.
How to use this tool
- Type a value in the Square Foot box to see it in acres, or type in the Acre box to convert the other way.
- Press ⇄ to swap the two units, or Load example for a typical value.
- Check the charts below for common values; for other units, open the Area converter.
Formula
Acre (ac) = Square Foot (ft²) × 0.0000229568411387
Square Foot (ft²) = Acre (ac) × 43560
Both factors come from exact definitions: 1 acre = 43560 square feet and 1 square foot = 0.0000229568411387 acres (shown to 12 significant digits).
Example
Two conversions worked with the same factors the converter uses:
10890 ft² × 0.0000229568411387 = 0.25 ac
2 ac × 43560 = 87120 ft²
Square Foot to Acre chart
Common values from square feet to acres, rounded to four decimal places.
| Square Foot (ft²) | Acre (ac) |
|---|---|
| 100 | 0.0023 |
| 500 | 0.0115 |
| 1,000 | 0.023 |
| 2,000 | 0.0459 |
| 2,500 | 0.0574 |
| 3,000 | 0.0689 |
| 4,000 | 0.0918 |
| 5,000 | 0.1148 |
| 6,000 | 0.1377 |
| 7,000 | 0.1607 |
| 7,500 | 0.1722 |
| 8,000 | 0.1837 |
| 9,000 | 0.2066 |
| 10,000 | 0.2296 |
| 12,000 | 0.2755 |
| 15,000 | 0.3444 |
| 20,000 | 0.4591 |
| 25,000 | 0.5739 |
| 30,000 | 0.6887 |
| 50,000 | 1.1478 |
| 100,000 | 2.2957 |
| 250,000 | 5.7392 |
| 1,000,000 | 22.9568 |
Acre to Square Foot chart
The reverse direction for values people often look up.
| Acre (ac) | Square Foot (ft²) |
|---|---|
| 0.05 | 2,178 |
| 0.1 | 4,356 |
| 0.15 | 6,534 |
| 0.2 | 8,712 |
| 0.25 | 10,890 |
| 0.33 | 14,374.8 |
| 0.5 | 21,780 |
| 0.75 | 32,670 |
| 1 | 43,560 |
| 1.5 | 65,340 |
| 2 | 87,120 |
| 5 | 217,800 |
| 10 | 435,600 |
Square-foot areas as fractions of an acre
| Area | Square Foot (ft²) | Acre (ac) |
|---|---|---|
| Parking stall of 9 ft by 18 ft, a common size | 162 | 0.0037 |
| Standard New York City lot, 25 ft × 100 ft | 2,500 | 0.0574 |
| Baseball infield, the 90 ft square inside the bases | 8,100 | 0.186 |
| Rood, an old English quarter acre | 10,890 | 0.25 |
| Football field between the goal lines, 300 ft × 160 ft | 48,000 | 1.1019 |
| Football field including both end zones | 57,600 | 1.3223 |
Quick mental estimate
Divide by 44,000, then add 1%: 22,000 ft² → 0.5 → 0.505 acre. The result is within about 0.01% of the exact 0.50505 acre, close enough for any lot.
Use the converter or the charts when the exact figure matters.
The two units
Square Foot (ft²): A square foot is the area of a square one international foot on each side, exactly 0.09290304 m² or 144 square inches. Historical areas based on the US survey foot use a slightly different factor.
Acre (ac): The acre used here is 43,560 international square feet, exactly 4,046.8564224 m². Historical US survey acres are slightly larger, so check the foot definition when interpreting old survey records.
Frequently asked questions
How many acres is 10,000 square feet?
About 0.23 acre (0.2296). A square plot 100 ft on each side has that area, a little under a quarter acre.
How do I turn a land price per square foot into a price per acre?
Multiply by 43,560. Land listed at 5 per square foot costs 217,800 per acre, and a price per acre divided by 43,560 gives the square-foot price.
Is a square foot of land the same as a square foot of floor space?
The unit is the same, but the two measure different things: lot area is the land inside the boundary, while floor area counts finished space on every story. A two-story house can have more square feet of floor than its footprint covers on the lot.
How precise is the result?
The converter uses the exact definitions above with browser floating-point arithmetic and shows up to 12 significant digits. The charts round to four decimal places for reading.
Sources
Last updated:
Page address with these inputs: https://kakao.mobile/tools/square-foot-to-acre-converter/
Cite or embed this tool
kakaoCalc. (2026, November 8). Square Feet to Acres Converter (ft² to ac). https://kakao.mobile/tools/square-foot-to-acre-converter/
“Square Feet to Acres Converter (ft² to ac).” kakaoCalc, 8 Nov. 2026, kakao.mobile/tools/square-foot-to-acre-converter/.
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