How many square feet equal an acer?

Answer 1

There are 43,560 square feet in an acre, assuming there are 3 feet in a yard.

Also assuming the question is about an acre (a measure of area) and not acre (a species of tree).

Answer 2

There are 4,840 square yards in a square acre ("acer" is a tree)

Answer 3

1 acre is equal to 43,560 square feet.