Square Inscribed in a Circle Calculator

Find the largest square that fits inside a circle. Enter the circle's radius or diameter to compute the inscribed square's side, area, and perimeter.

Enter Circle Dimensions

Inscribed Square

Square Side Length
9.899495
units
Square Area98
Square Perimeter39.597980
Square Diagonal14
Circle Radius7
Circle Area153.93804
Area Ratio (Sq/Circle)0.63662

Step-by-Step Solution

Understanding a Square Inscribed in a Circle

When a square is inscribed in a circle, all four vertices of the square lie on the circumference of the circle. The diagonal of the inscribed square equals the diameter of the circle. This is the largest possible square that can fit inside the circle.

Key Formulas

Side Length

The side of the inscribed square from the circle's radius.

s = r√2

Area of Inscribed Square

Using the relationship between the square and circle.

A = 2r²

Perimeter

Four times the side length.

P = 4r√2

Diagonal

The diagonal of the inscribed square equals the circle's diameter.

d = 2r

Derivation

The diagonal of the inscribed square is the diameter of the circle: d = 2r. Since the diagonal of a square with side s is s√2, we get s√2 = 2r, so s = 2r / √2 = r√2. The area is s² = (r√2)² = 2r².

Area Ratio

The ratio of the inscribed square's area to the circle's area is always 2/pi (approximately 0.6366). This means the inscribed square covers about 63.66% of the circle's area, regardless of the size of the circle.

Practical Applications

  • Cutting the largest square piece from a circular material (wood, metal, fabric).
  • Determining the maximum square display area within a circular frame.
  • Architecture and design for inscribed geometrical patterns.
  • Optimizing material usage in manufacturing.