Area calculator

Area and perimeter for rectangles, circles, triangles, trapezoids, ellipses, parallelograms, sectors and regular polygons.

Calculated in this browser. Nothing is sent anywhere.

Inputs in any consistent unit — results come back in that unit² / unit. Each dimension 0–1e+9; polygon sides 3–1000. Triangle area uses base × height (perimeter needs all three sides — use the triangle solver); ellipse circumference is the Ramanujan approximation; trapezoid needs all four sides for the perimeter.

How to use

  1. Pick a shape.
  2. Enter its dimensions in any consistent unit.
  3. Read the area and perimeter.

What it supports

Inputs in any consistent unit — results come back in unit² / unit. Each dimension 0–1e9; polygon sides 3–1,000. Triangle area is base × height; ellipse circumference is the Ramanujan approximation; a trapezoid needs all four sides for its perimeter.

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