Square Calculator: Side, Diagonal, Perimeter and Area
Choose which value you know, enter it, and the calculator finds the side first and then everything else.
- Nothing you type is stored
- Free
- No signup
Area
36cm²
- Side
- 6 cm
- Diagonal
- 8.4853 cm
- Perimeter
- 24 cm
Show working
- A = a² = 36 cm²
- P = 4a = 24 cm
- d = a√2 = 8.4853 cm
How to use
- Choose what you know: side, diagonal, perimeter or area.
- Enter the value and pick a unit.
- Read all four values and the working.
Good to know
Every square value comes from its side a: area a², perimeter 4a and diagonal a√2. Going backwards: a = √A, a = P/4 and a = d/√2.
The diagonal of a square is about 1.414 times its side. NCERT uses d²/2 as another way to get the area from the diagonal: a square with a 10 cm diagonal has an area of 50 cm².
Handy for square plots and rooms (area from one wall), tiles (side from area) and checking that a frame is square.
Questions
How do I find the side of a square from its area?
Take the square root: a = √A. An area of 144 m² gives a side of 12 m.
What is the diagonal of a square?
d = a × √2 ≈ 1.414 × side.
How do I find the area from the diagonal?
Area = d² ÷ 2.
What is the perimeter of a square?
4 × side.
Is anything I enter stored?
No. The calculation runs in your browser and nothing is sent to a server.