Square Perimeter Calculator

Calculate the perimeter of a square from its side length, area, or diagonal with step-by-step solutions.

Calculate From

Result

Perimeter
20
units
Side Length5
Perimeter20
Area25
Diagonal7.071068

Step-by-Step Solution

P = 4s = 4 x 5 = 20

Understanding Square Perimeter

The perimeter of a square is the total length of all four sides. Since all sides of a square are equal, the perimeter is simply four times the side length. The formula P = 4s is one of the most fundamental geometric relationships.

Perimeter Formulas for a Square

From Side Length

The most direct way to find the perimeter when you know the side length.

P = 4s

From Area

First find the side length by taking the square root of the area, then multiply by 4.

P = 4 x sqrt(A)

From Diagonal

The diagonal of a square relates to its side by d = s x sqrt(2), so s = d / sqrt(2).

P = 2d x sqrt(2)

Practical Applications

Knowing the perimeter of a square is essential in many real-world situations: fencing a square garden, framing a square picture, calculating the amount of trim needed for a square room, or determining the length of wire needed to enclose a square area.

Key Properties of a Square

  • All four sides are equal in length.
  • All four interior angles are 90 degrees.
  • The diagonals bisect each other at right angles.
  • The diagonal length is s x sqrt(2), where s is the side length.
  • The area is s2 and the perimeter is 4s.