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  1. Home
  2. Math Calculators
  3. Square Calculator

Square Calculator

Calculate square area, perimeter, diagonal, and inscribed/circumscribed circle properties. Enter any measurement and get all values instantly.

Formula:A = a² | P = 4a | d = a√2

Square Properties

Area

100.0000 cm^2

Side10.0000 cm
Perimeter40.0000 cm
Diagonal14.1421 cm

Square Input

Square Visualization

Showing inscribed circle (inside) and circumscribed circle (outside)

a = 10.00 cmd = 14.14r = 5.00

Complete Results

Side Length (a)

10.0000 cm

Area

100.0000 cm^2

A = a^2

Perimeter

40.0000 cm

P = 4a

Diagonal

14.1421 cm

d = a x sqrt(2)

Circle Properties

Inscribed Circle Radius

5.0000 cm

r = a/2

Circumscribed Circle Radius

7.0711 cm

R = d/2 = (a x sqrt(2))/2

Inscribed Circle Area

78.5398 cm^2

78.5% of square

Circumscribed Circle Area

157.0796 cm^2

63.7% filled by square

Square Reference Table

SideAreaPerimeterDiagonal
1141.414
2482.828
525207.071
101004014.142
204008028.284
50250020070.711
10010000400141.421

Square Formulas

Basic Formulas

  • Area: A = a^2
  • Perimeter: P = 4a
  • Diagonal: d = a x sqrt(2)

Finding Side From

  • From Area: a = sqrt(A)
  • From Perimeter: a = P/4
  • From Diagonal: a = d/sqrt(2)

Circle Formulas

  • Inscribed radius: r = a/2
  • Circumscribed radius: R = (a x sqrt(2))/2 = d/2
  • Ratio R/r = sqrt(2) = 1.414...

Key relationship: The diagonal of a square is always sqrt(2) times (about 1.414x) the side length. This comes from the Pythagorean theorem: d^2 = a^2 + a^2 = 2a^2.

Square Properties

Area

100.0000 cm^2

Side10.0000 cm
Perimeter40.0000 cm
Diagonal14.1421 cm

?How to Calculate Square Properties

Square formulas: Area = side x side = side squared. Perimeter = 4 x side. Diagonal = side x sqrt(2), approximately 1.414 x side. Inscribed circle radius = side / 2. Circumscribed circle radius = (side x sqrt(2)) / 2 = diagonal / 2.

What is a Square?

A square is a regular quadrilateral with four equal sides and four right angles (90 degrees each). It is both a special rectangle (with equal sides) and a special rhombus (with right angles). The diagonals of a square are equal, bisect each other at right angles, and each diagonal divides the square into two congruent isosceles right triangles.

Key Facts About Squares

  • Area = side squared = a^2
  • Perimeter = 4 x side = 4a
  • Diagonal = a x sqrt(2), approximately 1.414a
  • All four sides are equal in length
  • All four angles are 90 degrees (right angles)
  • Inscribed circle radius = a/2 (half the side)
  • Circumscribed circle radius = a x sqrt(2)/2 = diagonal/2
  • A square is a special rectangle and a special rhombus
  • Diagonals bisect each other at 90 degrees
  • Diagonals divide the square into 4 congruent right triangles

Quick Answer

Square formulas: Area = side x side = side squared. Perimeter = 4 x side. Diagonal = side x sqrt(2), approximately 1.414 x side. Inscribed circle radius = side / 2. Circumscribed circle radius = (side x sqrt(2)) / 2 = diagonal / 2.

Frequently Asked Questions

The area (A) of a square is calculated by squaring the side length: A = side x side = a^2. For example, a square with side 5 has area = 25 square units.

Area = side x side = a^2.

The diagonal (d) of a square equals the side multiplied by the square root of 2: d = a x sqrt(2) = a x 1.414... This comes from the Pythagorean theorem applied to the right triangle formed by two sides and the diagonal.

Diagonal = side x sqrt(2), approximately 1.414 x side.

The inscribed circle (incircle) is the largest circle that fits inside the square, touching all four sides. Its radius equals half the side length: r = a/2. The circle's area is pi x (a/2)^2.

Largest circle inside the square. Radius = side/2.

The circumscribed circle (circumcircle) is the smallest circle that completely contains the square, passing through all four corners. Its radius equals half the diagonal: R = (a x sqrt(2))/2 = d/2.

Smallest circle containing the square. Radius = diagonal/2.

To find the side from the area, take the square root: side = sqrt(Area). For example, if area = 36, then side = sqrt(36) = 6.

Side = sqrt(Area).

A square's diagonals are equal in length, bisect each other at right angles (90 degrees), and divide the square into four congruent right isosceles triangles. Each diagonal = side x sqrt(2).

Diagonals are equal, bisect at 90 degrees, length = side x sqrt(2).

Last updated: 2025-01-15

Square Properties

Area

100.0000 cm^2

Side10.0000 cm
Perimeter40.0000 cm
Diagonal14.1421 cm