Perimeter Calculator
Calculate the perimeter of various geometric shapes including rectangles, squares, circles, triangles, trapezoids, parallelograms, rhombuses, and regular polygons.
Shape Details
How to Use This Calculator
Select shape type
Choose from rectangle, square, circle, triangle, trapezoid, parallelogram, rhombus, pentagon, or hexagon from the dropdown menu.
Choose measurement unit
Select your preferred unit: centimeters, meters, inches, feet, or millimeters.
Enter dimensions
Input the required measurements for your selected shape. The form will show the appropriate fields.
View results
Perimeter is calculated automatically with the formula and explanation shown.
Perimeter Calculation Tips
Double-check your measurements before calculating to ensure accuracy.
For circles, remember that perimeter is called circumference.
Make sure all triangle sides can form a valid triangle (triangle inequality).
Use consistent units throughout your calculation.
Perimeter measures the total distance around the outside of a shape.
For irregular shapes, break them down into simpler shapes and add their perimeters.