HesapHanem

Square Calculator

Find a square’s area, perimeter and diagonal.

How it is calculated

From the side length a the tool works out three things: area A = a², perimeter P = 4a and diagonal d = a × √2 (the diagonal follows from Pythagoras, since it is the hypotenuse of a right triangle with two sides of length a). The side must be greater than zero. Results are rounded to two decimals. Units are whatever you enter: if the side is in metres, the perimeter and diagonal are in metres and the area is in square metres.

Worked example

A square tile has a side of 12. Area: 12² = 144. Perimeter: 4 × 12 = 48. Diagonal: 12 × 1.4142 ≈ 16.97. So the tile covers 144.00 square units, its edge is 48.00 long in total, and the corner-to-corner distance is 16.97.

Try this example →

Common mistakes

  • Reading the area in plain units. If the side is in cm the area is in cm², and converting to m² divides by 10 000, not by 100.
  • Confusing the diagonal with the side or perimeter when cutting material. The diagonal is about 1.41 times the side.
  • Entering the area or the perimeter in the side field. Divide the perimeter by 4 first.
  • Mixing units, such as a side in centimetres compared with a room measured in metres.

About this calculator

This calculator takes a square's side length and computes its area (side²), perimeter (4 × side), and diagonal (side × √2), the three measurements that fully describe a square's size.

It's used for everyday sizing tasks — tiling a square room, cutting a square piece of fabric or material, or fencing a square plot of land — as well as for geometry homework asking for area, perimeter and diagonal together. The diagonal is often the trickiest of the three since it requires the square root of 2, which this calculator handles instantly instead of requiring a manual Pythagorean calculation.

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Comments (1)

  • Editorial team

    All three results follow the unit you typed: a side in centimetres gives an area in square centimetres, and dividing by 10,000 converts it to square metres. On site, the diagonal is a handy squareness test for a frame, a patio or a tile layout. Measure corner to corner both ways and both readings should match the diagonal shown. Anything noticeably off means the shape is a rhombus or a skewed rectangle. What are you laying out?

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