1 acre = 43560 square feet
To convert from acres to square feet, you just need to multiply the value in acres by 43560 (the conversion factor).
So, 1 acre (the square footage of an acre) = 1 × 43560 = 43560 square feet.
The square root of 43,560, that is approximately 208.7 feet. So, a square with an area of 43,560 square feet would have the side length of 207.8 ft.
source: Full Unit Area Converter