Geometric Shape Perimeter Calculator

Quickly and accurately calculate the perimeter for various geometric shapes like squares, rectangles, triangles, and circles using this online tool.

Square

Rectangle

Triangle

Circle

Calculate Square Perimeter

Enter the side length of your square.

Calculate Rectangle Perimeter

Enter the length and width of your rectangle.

Calculate Triangle Perimeter

Enter the lengths of the three sides of your triangle.

Calculate Circle Perimeter (Circumference)

Enter either the radius or the diameter of your circle.

Select a shape and input dimensions to see the perimeter
Remaining Calculations: 3

How to Use This Perimeter Calculator

What is Geometric Perimeter?

The perimeter of a two-dimensional geometric shape is the total length of its boundary. For polygons like squares, rectangles, and triangles, it's the sum of all side lengths. For a circle, the perimeter is known as its circumference. This calculator helps you find these values easily.

Calculating the Perimeter of a Square

  1. Choose the "Square" option.
  2. Input the length of one side of the square.
  3. Click the "Calculate Now" button.
  4. The result will show: Perimeter = 4 × (Side Length).

Square Example:

If Side Length = 5 units

Calculated Perimeter = 4 × 5 = 20 units

Calculating the Perimeter of a Rectangle

  1. Select the "Rectangle" option.
  2. Enter the length and the width of the rectangle.
  3. Click "Calculate Now".
  4. The result will display: Perimeter = 2 × (Length + Width).

Rectangle Example:

If Length = 6 units, Width = 4 units

Calculated Perimeter = 2 × (6 + 4) = 20 units

Calculating the Perimeter of a Triangle

  1. Pick the "Triangle" option.
  2. Input the lengths of all three sides (Side A, Side B, Side C).
  3. Press "Calculate Now".
  4. The result shows: Perimeter = Side A + Side B + Side C. (Note: The sides must be able to form a valid triangle).

Triangle Example:

If Side A = 3 units, Side B = 4 units, Side C = 5 units

Calculated Perimeter = 3 + 4 + 5 = 12 units

Calculating Circle Circumference (Perimeter)

  1. Choose the "Circle" option.
  2. Enter either the radius or the diameter of the circle. (If you enter one, the other will auto-calculate).
  3. Click "Calculate Now".
  4. The result displays: Circumference = 2 × π × Radius (or π × Diameter).

Circle Example (using radius):

If Radius = 5 units

Calculated Circumference = 2 × π × 5 ≈ 31.42 units

Frequently Asked Questions (FAQ)

What is the formula used for a square's perimeter?

The perimeter of a square is found using the formula: P = 4s, where 's' is the length of one side of the square. Since all four sides of a square are equal, you multiply the side length by four.

How can I find the perimeter of an irregular polygon?

To find the perimeter of an irregular polygon, you need to measure the length of each of its sides and then sum these lengths. This calculator is designed for standard shapes (squares, rectangles, triangles, circles). For complex or irregular polygons, manual summation of side lengths is required.

What's the key difference between perimeter and area?

Perimeter is the total length of the boundary of a two-dimensional shape (a 1D measurement, e.g., in meters or feet). It's like walking around the edge of a field. Area is the measure of the surface enclosed by the boundary of a two-dimensional shape (a 2D measurement, e.g., in square meters or square feet). It's the space inside the field.

How precise are the perimeter calculations?

This calculator typically provides results with a precision of two decimal places. For calculations involving circles, the value of π (pi) is approximated (e.g., 3.14159). This level of accuracy is generally sufficient for most educational and practical purposes.

Why is there a limit on calculations?

A limited number of calculations are available to help support and maintain the service. You can unlock extended access for 30 days by completing a simple offer. This model helps ensure the tool remains available and allows for ongoing improvements.