Square Feet to Acres
An instant square feet-to-acres converter, with the formula and a reference table below.
| Square Feet | Acres |
|---|---|
| 1 ft² | 2.29568e-05 ac |
| 2 ft² | 4.59137e-05 ac |
| 3 ft² | 6.88705e-05 ac |
| 5 ft² | 0.000115 ac |
| 10 ft² | 0.00023 ac |
| 25 ft² | 0.000574 ac |
| 50 ft² | 0.001148 ac |
| 100 ft² | 0.002296 ac |
How to use
- Enter a value in the Square Feet field.
- The Acres figure appears immediately — no button to press.
- Typing in the Acres field converts back to Square Feet the same way.
- Use the reference table for the values that come up most often.
Square Feet to Acres formula
The factor from square feet to acres is 2.29568411e-05.
ac = ft² × 2.29568411e-05
Read in reverse, one acre is exactly 43,560 square feet.
Why this factor: the square foot and the acre are both defined against the square meter, so dividing one definition by the other gives 2.29568411e-05 directly. Both definitions are set out in full below.
To go the other way, divide by 2.29568411e-05 — or use the Acres to Square Feet converter, which is the same calculation reversed.
Worked example
Given 1000 ft², multiplying by 2.29568411e-05 yields 0.022957 ac.
1000 ft² × 2.29568411e-05 = 0.022957 ac
The converter above does this for any value you type, in either direction.
What is a square foot?
A square foot is the primary unit of floor area in the United States.
Definition: Exactly 0.09290304 square meter, following from the exact 0.3048 m foot.
Where it is used: US and Indian property listings, commercial leases, and paint and flooring coverage.
What is an acre?
An acre is the customary land area unit of the US and UK, historically a day's ploughing for one team of oxen.
Definition: One chain by one furlong — 43,560 square feet — which is exactly 4,046.8564224 square meters.
Where it is used: US and UK property and farmland, development parcels, and land sales.
Worth knowing: 640 acres make one square mile, the basis of the US Public Land Survey grid.
Square Feet vs Acres
The square foot and the acre belong to the same family of units, so converting between them is usually a matter of shifting a decimal point or applying a small whole-number factor.
Frequently asked questions
How many acres are in a square foot?
One square foot equals 2.29568411e-05 acres.
What is the formula to convert square feet to acres?
Multiply the number of square feet by 2.29568411e-05. To reverse it, divide by 2.29568411e-05 instead.
How do I convert acres back to square feet?
Divide by 2.29568411e-05, which is the same as multiplying by 43560.
How many acres are in 10 square feet?
10 ft² works out to 0.00023 ac.
Is there anything to watch out for with acres?
640 acres make one square mile, the basis of the US Public Land Survey grid.
How is the square foot defined?
Exactly 0.09290304 square meter, following from the exact 0.3048 m foot.