Areas & perimeters

Area and perimeter calculators for plane shapes: rectangle, circle, triangle, ellipse, and polygons. Results with units and formulas.

Circle area calculator

Compute area, circumference, radius, and diameter from any one value.

Compute area, perimeter, and diagonal from one side.

Compute area, perimeter, diagonal, and aspect ratio from two sides.

Compute area, perimeter, heights, and triangle type from sides or from base and height.

Compute parallelogram area, perimeter, and conversions using base-height, sides-angle, or diagonals-angle data.

Compute area, perimeter, and height from bases and height, or from sides and included angle.

Compute rhombus area, perimeter, and height from diagonals or from side and angle.

Compute circumference, radius and diameter from any single input with quick conversions.

Compute square perimeter, side and diagonal with instant conversions.

Compute a rectangle perimeter from sides, diagonal, or area with automatic conversions.

Compute a triangle perimeter from three sides, two sides plus angle or an equilateral side, including Heron area and quick conversions.

Compute a parallelogram perimeter from base and side with automatic conversions.

Compute a trapezoid perimeter from four sides, isosceles or right mode with instant unit conversions.

Find the perimeter of a rhombus from the side, diagonals, or an angle with instant conversions.