Area Calculator
Calculate the area of common shapes. Use the same unit for all measurements; the result is in square units.
| Shape | |
| Length | |
| Width |
Result
The area will appear here.
How it works
Area is the amount of surface inside a shape, measured in square units (like m² or ft²).
Common formulas
- Rectangle: A = length × width
- Circle: A = π × r²
- Triangle: A = ½ × base × height
- Trapezoid: A = ½ × (a + b) × height
Worked example
A rectangle 5 m by 3 m has area 15 m². A circle with radius 2 m has area about 12.57 m².
For general information only. Use consistent units.
How to use the Area Calculator
It takes a few seconds, and every figure is calculated in your browser.
- Pick the shape.
- Enter the length.
- Enter the width.
- Enter your height.
- Press Calculate — the result appears in the dark panel beside the form.
- Use Copy, CSV, Share or Print under the result if you want to keep it.
Area Calculator — frequently asked questions
What formula does the Area Calculator use?
Rectangle: A = length × width Circle: A = π × r² Triangle: A = ½ × base × height Trapezoid: A = ½ × (a + b) × height
How does the Area Calculator work?
Area is the amount of surface inside a shape, measured in square units (like m² or ft²).
Can you walk through a worked example?
A rectangle 5 m by 3 m has area 15 m². A circle with radius 2 m has area about 12.57 m².
Last updated 10 November 2026 · Formula, worked example and assumptions are documented above, and every result is calculated in your browser.