How many square feet are in an acre?
An acre is 43,560 square feet, which is 4,840 square yards or about 0.405 hectares. It's an area, not a shape: any region totaling 43,560 sq ft is an acre, whether it's a square (about 208.7 ft on a side) or a long strip. A common mental picture is roughly 90% of an American football field, minus the end zones.
Source: Exact conversion (1 acre = 43,560 sq ft) · Verify against your AHJ and the adopted code edition.
One acre = 43,560 square feet. It’s a fixed area, so the shape can be anything that adds up to that number:
- 4,840 square yards (43,560 ÷ 9)
- ≈ 0.405 hectares (metric)
- A perfect square would be about 208.7 ft on each side (√43,560).
To convert the other way, divide square footage by 43,560: a 21,780 sq ft lot is exactly half an acre.
A useful visual: an American football field including both end zones is about 1.32 acres, so an acre is roughly 90% of the field between the goal lines.
Work it out: the square footage calculator reports area in sq ft, sq yd, m², and acres from a length and width — handy for sizing a lot or a slab.