Area Calculator

Calculate the area of common 2D shapes: rectangle, triangle, circle, trapezoid, ellipse, sector, polygon, and more.

Shape & Dimensions

Area — Rectangle
40
square units
Perimeter / Circumference: 26
A = l × w

Area Formulas

ShapeFormula
SquareA = a²
RectangleA = l × w
Triangle (Base & Height)A = ½ × b × h
Triangle (3 Sides)A = √(s(s−a)(s−b)(s−c)), s = (a+b+c)/2 (Heron's)
CircleA = πr²
ParallelogramA = b × h
TrapezoidA = ½(a + b) × h
RhombusA = (d₁ × d₂) / 2
EllipseA = π × a × b
SectorA = (θ/360°) × πr²
Regular PolygonA = (n × s²) / (4 × tan(π/n))