Area Formulas Reference

ShapeFormulaVariables
RectangleL × WL = length, W = width
Circleπ × r²r = radius
Triangle½ × b × hb = base, h = height
Trapezoid½ × (a + b) × ha, b = parallel sides, h = height
Ellipseπ × a × ba, b = semi-axes
Parallelogramb × hb = base, h = height
Sector(θ/360) × π × r²θ = angle°, r = radius

Area Unit Conversions

FromToMultiply by
sq ftsq m0.0929
sq msq ft10.764
sq ftacres0.0000229568
acressq ft43,560
sq miacres640
hectaresacres2.471

Practical Area Estimates