Area Calculator
Calculate area of all geometric shapes: circle, rectangle, square, triangle, trapezoid, ellipse, and more. Area formulas with examples.
1x² − 5x + 6 = 0
Discriminant = 1
two real roots
x = (−b ± √(b²−4ac)) / 2a
x₁ = 3
x₂ = 2
About the Area Calculator
Calculating the area of geometric shapes is a fundamental skill for home improvement, landscaping, real estate, and countless other practical applications. Our area calculator handles 12 common shapes: square, rectangle, circle, triangle, trapezoid, ellipse, parallelogram, rhombus, pentagon, hexagon, octagon, and annulus (ring) — with instant results in any unit of measurement.
Formula
Circle: A = πr² | Rectangle: A = lw | Triangle: A = ½bh | Trapezoid: A = ½(a+b)h
How It Works
Each shape has a specific area formula. Circle: A = πr². Rectangle: A = length × width. Triangle: A = ½ × base × height. Trapezoid: A = ½ × (a + b) × h where a and b are parallel sides. Ellipse: A = πab where a and b are semi-axes. Our calculator accepts inputs in feet, metres, inches, or centimetres and converts automatically, preventing the common error of mixing units.
Tips & Best Practices
- ✓Irregular areas can be approximated by breaking them into regular shapes and summing.
- ✓For land area: 1 acre = 43,560 sq ft = 4,047 m². 1 hectare = 10,000 m².
- ✓Paint coverage: 1 gallon typically covers 350-400 sq ft with one coat.
- ✓Flooring: add 10% waste factor to measured area for cuts and errors.
- ✓Grass seed: coverage printed on bags assumes measured area — always measure before buying.
Who Uses This Calculator
Homeowners calculating paint, flooring, or tile quantities, landscapers estimating grass seed or mulch needs, real estate appraisers measuring floor plans, students solving geometry problems, and engineers calculating material quantities all use area calculations.
Optimised for: USA · Canada · UK · Australia · Calculations run in your browser · No data stored
Frequently Asked Questions
What is the formula for area of a circle?
Area = π × r² where r is radius. For a circle with radius 5: area = π × 25 ≈ 78.54 square units.