Area Calculator
Compute area for multiple geometric shapes using standard scientific formulas.
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Shape Selection
Shape Dimensions
m
Result
Enter the required details and click calculate to view results.
All calculations assume ideal planar geometry and consistent units.
Geometry guide
Area Calculator
Area tells you how much flat space a shape covers. It comes up when you're estimating flooring, planning a garden bed, checking a drawing, or doing a geometry problem. Choose a shape, enter its measurements in meters or centimeters, and the calculator shows the area with the formula used.
How to use the calculator
- 1Choose the shape: circle, rectangle, triangle, trapezium, ellipse, or sector.
- 2Select meters or centimeters as the length unit. Use the same unit for all length measurements in that calculation.
- 3Enter the dimensions shown. For a sector, enter the radius and central angle in degrees.
- 4Select Calculate and read the result, including the formula and the squared unit (m² or cm²).
Formulas and what to measure
| Shape | Formula | Measurements |
|---|---|---|
| Circle | A = πr² | Radius, center to edge |
| Rectangle | A = length × width | Two perpendicular sides |
| Triangle | A = ½ × base × height | Base and perpendicular height |
| Trapezium | A = ½ × (a + b) × h | Parallel sides a and b, and their perpendicular distance h |
| Ellipse | A = πab | Semi-major axis a and semi-minor axis b |
| Circle sector | A = (θ ÷ 360) × πr² | Radius and central angle θ in degrees |
For example, a 4 m by 3 m rectangle has an area of 12 m². A circle with a 2 m radius has an area of about 12.5664 m². Results are displayed to four decimal places; the tool calculates from your entered dimensions before rounding the display.
Find the flat surface area before separately checking material coverage and waste.
Compare room, garden, or land measurements in a consistent unit.
Check homework and review how a shape's dimensions affect its area.
Split an irregular outline into simple shapes, then add or subtract their areas.
Frequently asked questions
Which measurements should I enter?
Does the tool convert between square meters and square centimeters?
What does height mean for a triangle or trapezium?
How do I find the area of an irregular room or plot?