Area Calculator: Formulas for Every Shape

Calculating area is a fundamental skill used in construction, interior design, gardening, and everyday problem-solving. Whether you need to paint a wall or tile a floor, knowing the right formula saves time and money.

Area Formulas for Common Shapes

Shape	Formula	Variables
Square	a²	a = side length
Rectangle	l × w	l = length, w = width
Triangle	(b × h) / 2	b = base, h = height
Circle	pi × r²	r = radius
Trapezoid	((a + b) / 2) × h	a, b = parallel sides, h = height
Parallelogram	b × h	b = base, h = height
Ellipse	pi × a × b	a, b = semi-axes

Worked Examples

Rectangle

A room is 5m long and 4m wide.

Area = 5 × 4 = 20 m²

Circle

A circular garden has a radius of 3m.

Area = pi × 3² = pi × 9 = 28.27 m²

Triangle

A triangular plot with base 10m and height 6m.

Area = (10 × 6) / 2 = 30 m²

Unit Conversions for Area

From	To	Multiply By
m²	cm²	10,000
m²	ft²	10.764
ft²	m²	0.0929
acres	m²	4,046.86
hectares	m²	10,000

Practical Applications

Home improvement: Calculate paint, flooring, or wallpaper needed

Gardening: Determine soil, mulch, or sod requirements

Real estate: Understand property sizes and lot dimensions

Construction: Plan material quantities for projects

Education: Geometry homework and exam preparation

Tips for Accurate Measurements

Always use the same unit for all measurements

For irregular shapes, break them into simpler shapes and add the areas

Remember that area is always expressed in squared units (m², ft², cm²)

Double-check your measurements before calculating

Try It Yourself

Calculate the area of any shape with our free Area Calculator. Select a shape, enter your measurements, and get instant results.