MihsabaA square has four equal sides. Perimeter is therefore four times its side. If you know area, recover the side with a square root. If you know the diagonal, divide by the square root of two before finding the perimeter.
Formula
P = 4s; from area A: P = 4√A; from diagonal d: P = 2√2 × d.
How to calculate
- Determine whether your known measurement is the side, area or diagonal.
- Convert the known measurement to the side length.
- Multiply the side by four; perimeter uses length units, not square units.
Worked examples
| Scenario | Calculation | Answer |
|---|---|---|
| Side 7 cm | 4 × 7 | 28 cm |
| Area 36 cm² | 4 × √36 | 24 cm |
| Diagonal 10√2 cm | 4 × 10 | 40 cm |
Important limitation
Perimeter is measured in units such as metres or centimetres. Area is measured in square units; 36 cm² is not the same measurement as 36 cm.
Common question
Can I calculate square perimeter from its area alone?
Yes. For nonnegative area, perimeter equals four times the square root of area.
Try the calculator: Perimeter of a Square Calculator – P = 4 × Side