Area Calculator

What this tool does

Calculate area instantly in your browser. All measurements are in the same unit, so area comes out in that unit squared. Heights are perpendicular distances.

How to use the Area Calculator

1. Enter or select shape.
2. Enter or select side (square).
3. Enter or select length (rectangle).
4. Enter or select width (rectangle).
5. Enter or select base (triangle).
6. Enter or select height (triangle).
7. Enter or select radius (circle / sector).
8. Enter or select sector angle (degrees).
9. Enter or select parallel side 1 (trapezoid).
10. Enter or select parallel side 2 (trapezoid).
11. Enter or select height (trapezoid).
12. Enter or select semi-major axis a (ellipse).
13. Enter or select semi-minor axis b (ellipse).
14. Enter or select base (parallelogram).
15. Enter or select height (parallelogram).
16. Read the calculated result; change any measurement to compare alternatives.

Formula

Square s²; rectangle l×w; triangle ½bh; circle πr²; trapezoid ½(a+b)h; sector (θ/360)πr²; ellipse πab; parallelogram bh — each shape uses its perpendicular height, not a slanted side.

shape

Shape

side

Side (square)

length

Length (rectangle)

width

Width (rectangle)

tBase

Base (triangle)

tHeight

Height (triangle)

radius

Radius (circle / sector)

sAngle

Sector angle (degrees)

trapA

Parallel side 1 (trapezoid)

trapB

Parallel side 2 (trapezoid)

trapH

Height (trapezoid)

ellA

Semi-major axis a (ellipse)

ellB

Semi-minor axis b (ellipse)

pBase

Base (parallelogram)

pHeight

Height (parallelogram)

All measurements are in the same unit, so area comes out in that unit squared. Heights are perpendicular distances.

Worked example

For area calculator, the following measurements illustrate the exact method: Shape: rectangle; Side (square): 5; Length (rectangle): 10; Width (rectangle): 6; Base (triangle): 10; Height (triangle): 6; Radius (circle / sector): 5; Sector angle (degrees): 90; Parallel side 1 (trapezoid): 8; Parallel side 2 (trapezoid): 12; Height (trapezoid): 5; Semi-major axis a (ellipse): 6; Semi-minor axis b (ellipse): 4; Base (parallelogram): 10; Height (parallelogram): 6.

Results explained

Area

Area from the formula above. All measurements are in the same unit, so area comes out in that unit squared. Heights are perpendicular distances.

Perimeter / circumference (where defined)

Perimeter / circumference (where defined) from the formula above. All measurements are in the same unit, so area comes out in that unit squared. Heights are perpendicular distances.

Frequently asked questions