One side defines a square
All four sides are equal, so one side length is enough to calculate area, perimeter and diagonal.
Example
If the side length is 6, the area is 6 x 6 = 36 square units. The perimeter is 24 units, and the diagonal is about 8.49 units.
How to use the result
Use square area when estimating surface coverage such as tiles, paint, fabric or land. Use perimeter when estimating edging or trim around the outside.
Common mistakes
Area is in square units, not ordinary length units. If the side is measured in meters, the area is square meters.
Last reviewed: 2026-05-17