The Perimeter Calculator calculates the perimeter or circumference of six common shapes and converts the result between metres, feet, centimetres, and inches.
Formulas
- Square:
P = 4s. - Rectangle:
P = 2(l + w). - Circle:
C = 2 pi r. - Triangle:
P = a + b + c, subject to the triangle inequality. - Parallelogram:
P = 2(a + b). - Trapezoid:
P = a + b + c + d.
Example
A rectangle measuring 6 m by 4 m has perimeter 2 x (6 + 4) = 20 m. The calculator also returns 65.62 ft, 2,000 cm, and 787.40 in using standard conversions.
Questions
Is circle perimeter called circumference?
Yes. The calculator uses circumference terminology for a circle and perimeter for polygons.
Does it validate triangles?
Yes. The sum of any two sides must be greater than the third side.
Does the result include area?
No. Perimeter measures the boundary length; area is a separate calculation.
Limitations
The tool models the listed shapes with positive dimensions and does not calculate curved or irregular boundaries.