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Square calculator

All four measures of a square from any one. Give the side, the area, the perimeter or the diagonal and it returns the rest — side s, area s², perimeter 4s and diagonal s√2 — instantly.

Related tools

All Geometry tools →
Square diagonal calculatorCompute the diagonal and area of a square from its side length.Magic square generatorGenerate a magic square of any order from 3 to 20 — a grid of the numbers 1…N² where every row, column and diagonal adds to the same magic constant. It picks the right construction automatically: the Siamese method for odd orders, diagonal complements for multiples of four, and the Strachey method otherwise.Rectangle calculatorEvery property of a rectangle from any two you know. Pick what you have — length & width, area & a side, perimeter & a side, or diagonal & a side — and it returns the length, width, area, perimeter and diagonal, using A = l·w, P = 2(l+w) and d = √(l²+w²).Regular polygon calculatorEvery measure of a regular polygon from the number of sides and the side length: the area, perimeter, interior and exterior angles, the sum of interior angles, the apothem (inradius), the circumradius and the number of diagonals. One entry, the full geometry — for triangles through many-sided polygons.Equilateral triangle calculatorCompute the area, height and perimeter of an equilateral triangle from its side.Triangle area calculator (Heron's formula)Compute a triangle's area from the length of its three sides.Perimeter calculatorCompute the perimeter of a rectangle, square, circle or triangle.Rectangle diagonal calculatorCompute the diagonal, area and perimeter of a rectangle.

The Square calculator turns Input type, Value into Side, Area, Perimeter, Diagonal, instantly and for free. For instance, with Input type = Side (s) and Value = 5 it returns Side = 5, Area = 25 and Perimeter = 20.

How to use it

  1. Enter your values: Input type, Value.
  2. Read the result instantly: Side, Area, Perimeter, Diagonal.

Frequently asked questions

How does the Square calculator work?

It takes Input type and Value and derives Side, Area, Perimeter and Diagonal from them. The calculation is live as you type, so the result updates on every change.

Which values does the calculator ask for?

2 values: Input type and Value. Nothing else is required — no account, no file upload.

What does a typical calculation look like?

With Input type = Side (s) and Value = 5, the calculator returns Side = 5, Area = 25 and Perimeter = 20. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

How much does the result change with different inputs?

It moves a lot. Using Input type = Area (A) and Value = 10 instead, Side goes from 5 to 3.162 — which is why it is worth testing a few scenarios rather than trusting a single figure.

Which “Input type” option should I choose?

You can pick between « Side (s) », « Area (A) », « Perimeter (P) » and « Diagonal (d) ». Each one changes what the calculator works out, so switch and compare — the default is « Side (s) ».

What does it give for smaller values?

Scaled down to Input type = Side (s) and Value = 3, Side comes out at 3. The relationship is worth checking at both ends before you rely on a single result.

When would I actually use this?

Homework and site work alike: how much paint a wall takes, how much water a tank holds, whether a corner is square — and, on the coordinate side, the slope between two points, the distance across a plan, the midpoint of a span.

What is the most common mistake?

Mixing units inside one shape. Entering a length in centimetres and a width in metres gives an area wrong by a factor of a hundred, and the result looks perfectly plausible.

What is the difference between the Square calculator and the Square diagonal calculator?

Both return Area and Diagonal. What differs is what they ask for: this one wants Input type and Value, the Square diagonal calculator wants Side length. Use whichever matches the numbers you already have.

Is there a tool for the next step?

Magic square generator is the closest one after this: Generate a magic square of any order from 3 to 20 — a grid of the numbers 1…N² where every row, column and diagonal adds to the same magic constant. It picks the right construction automatically: the Siamese method for odd orders, diagonal complements for multiples of four, and the Strachey method otherwise.

Further reading

All guides →
How-toHow to Find the Area of a Triangle: Base × Height and Heron's FormulaTwo reliable ways to find a triangle's area: half base times height when you know the height, and Heron's formula when you only know the three sides.How-toHow to Calculate the Square Metres of a RoomFind a room's area by multiplying length by width. Here's the method for rectangular, L-shaped and round rooms, and why area drives your material orders.ExplainerThe Flat Pattern of a Cone Is a Sector, Not a CircleRoll a 50 mm cone 80 mm tall and its pattern is a 190.8° slice of a 94 mm circle. Flatten a nearly cylindrical lampshade and the pattern radius runs to 839 mm — the shallower the taper, the further away the apex.How-toHow to Find the Distance Between Two PointsUse the distance formula d = √((x₂−x₁)² + (y₂−y₁)²) to measure the straight-line distance between two points on a plane, with a worked example and the midpoint too.How-toHow to Calculate the Slope of a Line: Rise Over RunFind the slope of a line from two points with m = (y₂ − y₁) / (x₂ − x₁), and read what a positive, negative, zero, or undefined slope tells you.ExplainerThe Pythagorean Theorem ExplainedIn a right triangle, a² + b² = c². Here's what the formula means, a worked example, how to find any side, and where it's used in real life.