Square Area Calculator
Calculate the area, perimeter, and diagonal of a square from its side length.
- Free to use
- Accurate results
- No registration required
- Works on all devices
Enter a square's side length to calculate its area, perimeter, and diagonal.
Your result
25
Area
Perimeter20
Diagonal7.071
AI explanation
Formula
Area = side²; Perimeter = 4 × side; Diagonal = side × √2Worked example
Square with side 5
| Field | Value |
|---|---|
| Side length | 5 |
| Area | 25 |
| Perimeter | 20 |
| Diagonal | 7.0711 |
Assumptions
- All four sides of a square are equal by definition.
Frequently asked questions
How is the area of a square calculated?
Area = side × side (side squared) — since all four sides are equal, you only need to know one measurement.
How is the diagonal of a square calculated?
Diagonal = side × √2, which comes from the Pythagorean theorem applied to the right triangle formed by two sides and the diagonal.
What if length and width aren't equal?
Then it's a rectangle, not a square — use the Rectangle Calculator, which takes both measurements separately.