Acres to Square Feet Converter
Multiply an area in acres by 43560 to get square feet. 1 ac = 43560 ft², and 0.25 ac = 10890 ft², the size of a quarter-acre lot.
An acre is a measure of area, not of shape. A one-acre lot can be square, long and narrow, or irregular, and still be 43,560 square feet.
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(opens in a new tab)How to convert acres to square feet
Formula: square feet = acres × 43560
The constant is exact by definition: 1 acre = 43560 square feet. It is not a rounded approximation.
The acre has long been the area of a strip one furlong (660 ft) long and one chain (66 ft) wide, and 660 × 66 = 43,560. Its modern definition keeps that exact number of square feet, so a whole or simple fraction of an acre converts to a whole number of square feet.
Worked example: 0.25 ac to square feet
This result is complete, not rounded.
Convert 0.25 ac
Input
0.25 ac
Output
0.25 × 43560 = 10890 ft²
Common acres to square feet conversions
| Acres (ac) | Square feet (ft²) |
|---|---|
| 0.25 ac | 10890 ft² |
| 0.5 ac | 21780 ft² |
| 1 ac | 43560 ft² |
| 2 ac | 87120 ft² |
| 5 ac | 217800 ft² |
| 10 ac | 435600 ft² |
| 20 ac | 871200 ft² |
When you need to convert acres to square feet
- Lot and land sizes in property listings, given in acres.
- Site planning: checking how much of a lot a building or yard would take up in square feet.
- Farm, garden and field areas.
- Comparing a land area with a building's floor area, which is usually quoted in square feet.
Things worth knowing
- Acres here are international acres. The US survey acre, used in some older land records, differs by about four parts per million and is not converted.
- Converting an area does not say anything about the value of a property. This page converts units only.
Converting back and related converters
To go the other way, use the Square Feet to Acres Converter, which applies acres = square feet / 43560. For any other pair of units, open the Unit Converter, or browse every unit converter.
- Square Feet to Square Meters Converter: to turn the square feet into square meters.
- Square Meters to Square Feet Converter: for areas measured in square meters.
Frequently asked questions
How many square feet are in one acre?
Exactly 43560 square feet. That is the definition of the acre.
How many square feet is half an acre?
0.5 ac = 21780 ft², exactly half of the 43,560 square feet in a whole acre.
Why is an acre such an odd number of square feet?
It comes from older land measures: a furlong of 660 feet by a chain of 66 feet. The number was kept when the acre was defined in feet.
How does an acre compare with a hectare?
A hectare is 10,000 square meters, about 2.47 acres. The Unit Converter converts acres to hectares and square meters.