Square Calculator

About this calculator

A square's geometry is fully determined by a single measurement — its side length, s — because every other property follows directly from it: area = s², perimeter = 4s, and diagonal = s√2, the last coming straight from the Pythagorean theorem applied to the right triangle formed by two sides and the diagonal.

This makes the square one of the first shapes taught in geometry precisely because it demonstrates how multiple formulas (area, perimeter, and the Pythagorean theorem) connect through one variable, and the same three figures are used constantly outside the classroom — flooring and tiling estimates, framing and fencing material calculations, and any layout task where a square footprint's diagonal matters, such as squaring a foundation or a garden bed using the 3-4-5 method's diagonal check.

This calculator takes a square's side length and returns its area, perimeter, and diagonal.