What is the difference between perimeter and area?

Perimeter is the one-dimensional distance around the outside of a shape, measured in linear units (like feet or meters). Area is the two-dimensional space inside the shape, measured in square units (like square feet or square meters). For example, a fence for a garden relates to its perimeter, while the amount of soil needed to fill it relates to its area.

What is circumference?

Circumference is the specific term for the perimeter of a circle. It is the total distance around the edge of the circle.

Can I calculate the perimeter of an irregular shape with this calculator?

This calculator is designed for common, regular shapes (squares, rectangles, circles). To find the perimeter of an irregular shape, you would need to measure and add up the lengths of all of its individual sides manually.

Perimeter Calculator

Calculate the perimeter of common geometric shapes.

Perimeter of a Square

Side Length (a)

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About the Perimeter Calculator

Learn what perimeter is and how to calculate it for various shapes.

What is Perimeter?

Perimeter is the total distance around the outside of a two-dimensional shape. It's the length of the outline or boundary of any flat object. Imagine walking along the edge of a field; the total distance you walk would be its perimeter. For a circle, this specific type of perimeter is called the circumference. Understanding perimeter is a fundamental concept in geometry and is essential for many practical tasks, such as fencing a yard, framing a picture, or any project that requires measuring a boundary.

How to Use This Calculator

Our Perimeter Calculator is designed for ease of use. To find the perimeter of a shape, first select the appropriate tab at the top: 'Square', 'Rectangle', or 'Circle'. Once you've selected the shape, input the required dimensions into the fields provided—for example, the side length for a square or the radius for a circle. After entering the measurements, click the "Calculate" button, and the result for the perimeter or circumference will be displayed instantly.

Formulas Used for Calculation

This calculator uses standard, universally accepted geometric formulas to ensure you get accurate results:

Square: Since all four sides of a square are equal, the perimeter is simply the side length multiplied by four. Formula: P = 4 × side.
Rectangle: The perimeter of a rectangle is found by adding the lengths of all four sides. Since opposite sides are equal, the formula is twice the sum of its length and width. Formula: P = 2 × (length + width).
Circle (Circumference): The distance around a circle is calculated using the formula C = 2πr, where 'r' is the radius (the distance from the center to the edge) and π (pi) is a mathematical constant approximately equal to 3.14159.

Practical Applications

Calculating perimeter is a common and necessary task in many real-world scenarios, far beyond just math homework:

Home Improvement & Gardening: Determine how much fencing material you need to enclose a garden or yard, or the length of baseboard molding required to go around a room.
Crafts & Decorating: Calculate the length of ribbon needed to wrap around a gift box, the amount of fabric for the border of a quilt, or the length of trim needed to frame a picture or mirror.
Construction: Estimate the length of material needed for building frames, window casings, or decorative trim.
Fitness & Sports: Measure the perimeter of a running track, a park, or a sports field to know the exact distance of one lap, helping you to track your workouts accurately.