Area Calculator

Free online area calculator for rectangle, triangle, circle, trapezoid, ellipse, sector, and parallelogram. Calculate surface area with step-by-step formulas for geometry and construction.

The Area Calculator helps you calculate the surface area of common geometric shapes. Select a shape, enter dimensions, and get instant area calculations with formulas and explanations.

Rectangle

Triangle (Base & Height)

Circle

Trapezoid

Ellipse

Circle Sector

Parallelogram

What is Area?

Area is the measure of the two-dimensional space enclosed by a shape's boundary. It's expressed in square units (m², ft², cm², etc.). Area calculations are fundamental in construction (flooring, painting), landscaping (sod, mulch), manufacturing (material cutting), and engineering (structural design). Each geometric shape has a specific formula for calculating area based on its dimensions.

Area Formulas by Shape

Rectangle: A = L × W

Triangle: A = (b × h) / 2

Circle: A = π × r²

Trapezoid: A = [(a + b) / 2] × h

Ellipse: A = π × a × b

Sector: A = (θ/360) × π × r²

Parallelogram: A = b × h

Applications

Construction: Flooring materials, paint coverage, roofing
Landscaping: Sod, mulch, gravel coverage
Real estate: Property size, room dimensions
Manufacturing: Material cutting, sheet metal work
Agriculture: Field size, irrigation coverage
Interior design: Carpet, tile, wallpaper quantities
Engineering: Structural calculations, load distribution

Tips for Area Calculations

Always use consistent units - don't mix feet and meters
For irregular shapes, break into simple shapes and sum areas
Add 5-10% extra for material waste when purchasing
Perimeter ≠ Area - they measure different things
Round measurements affect area significantly - measure precisely
For triangles, ensure the three sides can form a valid triangle
Double-check which dimension is the perpendicular height