What this calculator does
Area measures the amount of flat space inside a shape. This calculator covers the most common classroom and practical shapes.
Formula used
Rectangle area is length times width. Triangle area is base times height divided by 2. Circle area is pi times radius squared. Trapezium area is the average of the parallel sides times height.
How to read the result
The answer is in square units based on the units you enter. If you enter metres, the result is square metres.
Assumptions
- All measurements must use the same unit.
- Uses pi from JavaScript Math.PI.
- Does not account for irregular shapes.
Sources and checks
This calculator uses a standard public formula. Where rules or thresholds can change, source links are listed on the relevant page.
Frequently asked questions
Why does area use square units?
Area counts two-dimensional space, so a length unit is multiplied by another length unit.