If you have ever wanted to install a fence or apply fertilizer to your lawn, you need to know how many square feet in an acre. Many yard and garden supply products are sold by the square foot, yet most areas of land are determined in acres. Being able to convert between the two makes it much easier to do work in your yard.

1. An acre is equal to 43,560 square feet, a number that is easily found with a little simple math. To determine the square feet of any area, you need to multiply the length in feet by the width in feet. This result is the square foot of the area. Once you know the width and length of an area you can determine the square feet of it quickly. The hardest part may be finding what the length and width is in feet.

2. An acre is a square piece of land that is roughly 208.71 feet on each side. This is the imperial, U.S. customary system used for land planning, agriculture and forestry. Multiplying 208.71 by 208.71 equals 43,559.86, which is rounded up to 43,560 square feet. When dealing with real estate or architecture, square feet is the standard used over acres.

Knowing this simple trick of multiplication will help anyone determine not only how many square feet are in an acre, but also how many square feet are in any piece of land. By just multiplying the length by the width in feet, the square feet of an area is simple to find.