A walkthrough, end to end.
- 1
Pick a shape — square, rectangle, circle, triangle, or parallelogram.
- 2
Enter the dimensions in any consistent unit.
- 3
See perimeter (or circumference for circles).
Perimeter formulas
Square 4s. Rectangle 2(l+w). Circle 2πr. Triangle a+b+c. Parallelogram 2(a+b).
What you can do with this.
Fencing a yard
Compute total fence length around a rectangular lot.
Framing a picture
Total length of trim needed.
Running a track
Circumference of a circular path.
Garden border
Length of edging required.
Geometry homework
Verify perimeter problems quickly.
Painting trim
Total perimeter of a room baseboard.
Sewing borders
Material needed to finish a rectangular cloth.
Perimeter 2026 — what's current
Foundational geometry; calculator wins for instant computation.
Frequently asked.
Whatever you enter — the result is in those linear units.
For regular polygons, P = n × s. Use the basic calculator.
No. Calculations run in your browser.
Yes — for circles and other curves, perimeter is called circumference.