Frequently Asked Questions
What is perimeter?
Perimeter is the total distance around the outside of a two-dimensional shape.
How do you calculate the perimeter of a rectangle?
Perimeter = 2 × (length + width). Add the length and width, then multiply by 2.
What is the perimeter (circumference) of a circle?
Circumference = 2 × π × radius, or π × diameter.
How do you find the perimeter of a triangle?
Add all three side lengths together: Perimeter = a + b + c.
What is the perimeter formula for a regular polygon?
Perimeter = n × side length, where n is the number of sides.
How do you calculate the perimeter of a trapezoid?
Add all four sides: Perimeter = a + b + c + d.
What units does this calculator use?
Any unit (meters, feet, inches, cm) — just be consistent with your input units.
What is the difference between perimeter and area?
Perimeter is the distance around a shape (1D), area is the space inside (2D).