Area of a Square Formula

Geometry Formulas: Area, Volume, Perimeter
Formula:

What is the formula for the area of a square?

Answer

Area of a square
A = a²

Here a is the side (or base). The result comes out in square units.

Where the formula comes from

A = a²

A square is a rectangle whose two sides are equal, so a · b becomes a · a. Nothing else changes.

Worked examples

Let a = 7. Then the area of a square = 49 square units.

Let a = 2.5. Then the area of a square = 6.25 square units.

The common mistake

Confusing a² with 2a. Squaring is a side times a side, not a side doubled: for a = 7 the area is 49, not 14.

Other quantities: Square

See Also

Geometry Formulas: Area, Volume, Perimeter

These are the formulas for the area, perimeter, circumference, volume and surface area of the standard shapes — 31 of them. Each page shows not only the formula but where it comes from, what every letter stands for, two worked examples and the mistake that this particular shape invites. For example, it can help you find out what is the formula for the area of a square? (The answer is: A = a²). Pick the pair — "Area of a circle", for instance — and hit the "Find out" button.
Geometry Formulas: Area, Volume, Perimeter
Formula:

Values from the Formula

If a =Area
11 square unit
24 square units
39 square units
416 square units
525 square units
10100 square units

FAQ

What is the formula for the area of a square?

Area of a square A = a²

Where does this formula come from?

A square is a rectangle whose two sides are equal, so a · b becomes a · a. Nothing else changes.

What is the most common mistake here?

Confusing a² with 2a. Squaring is a side times a side, not a side doubled: for a = 7 the area is 49, not 14.

How do I use this formula?

Put your own numbers in place of the letters. With a = 2.5, for instance, the formula A = a² gives = 6.25 square units.