Perimeter Calculator
Calculate the perimeter of various geometric shapes including rectangles, squares, triangles, circles, and polygons. Get instant results with step-by-step explanations.
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Shape Selection
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What is Perimeter?
The perimeter is the total distance around the outside of a two-dimensional shape. It's calculated by adding up the lengths of all the sides of the shape. Perimeter is measured in linear units such as centimeters, meters, inches, or feet.
Perimeter Formulas:
- Rectangle: P = 2 × (length + width)
- Square: P = 4 × side length
- Triangle: P = side₁ + side₂ + side₃
- Circle (Circumference): P = 2 × π × radius or P = π × diameter
- Regular Polygon: P = number of sides × side length
- Irregular Polygon: P = sum of all side lengths
Applications of Perimeter:
- Fencing and boundary calculations
- Construction and architecture planning
- Landscaping and garden design
- Sports field measurements
- Fabric and material requirements
- Security system installations
How Our Calculator Works:
Simply select the shape type, enter the required measurements, and our calculator will instantly compute the perimeter using the appropriate formula. The tool provides both the result and the calculation steps for better understanding.
Frequently Asked Questions
How do I calculate perimeter?
Perimeter is the total distance around a shape. For a rectangle it is 2 × (length + width); for a circle (circumference) it is 2 × π × radius.
What is the difference between perimeter and area?
Perimeter measures the distance around the edge (in linear units), while area measures the surface inside (in square units). A fence needs perimeter; paint needs area.
How do I find the perimeter of a triangle?
Add the lengths of all three sides. A triangle with sides 3, 4, and 5 has a perimeter of 12 units.
What is the perimeter of a circle called?
The perimeter of a circle is called its circumference, calculated as 2πr (or π × diameter).