Shape Area Calculator
2D area formulas made simple. Calculate area of circle, triangle and rectangle.
How does the shape area calculator work?
This calculator covers the three most common 2D shapes: circle, triangle, and rectangle. Select the shape, enter the required dimensions (radius for circle; base and height for triangle; length and width for rectangle), and click "Calculate". The tool applies the standard geometric formulas — π × r² for circle, ½ × base × height for triangle, and length × width for rectangle — giving you the exact area instantly.
How to use the Shape Area Calculator
Choose a shape from the dropdown menu. The input fields update automatically to show only the dimensions needed for that shape. Enter the values in your preferred units (all calculations are unit‑independent), then click "Calculate" to see the area. Switch between shapes at any time — the calculator resets and adapts immediately.
Example calculations
Circle with radius 5 → Area = π × 5² ≈ 78.54 square units. Triangle with base 6 and height 4 → Area = ½ × 6 × 4 = 12 square units. Rectangle with length 8 and width 3 → Area = 8 × 3 = 24 square units. The calculator delivers precise results for all shapes in milliseconds.
Frequently Asked Questions
What units does the calculator use?
The calculator works with pure numbers and does not enforce a specific unit. If you enter values in meters, the area is in square meters; in inches, square inches; in centimeters, square centimeters. Always use consistent units for all dimensions of a single calculation.
Can I calculate the area of other shapes?
This version focuses on circle, triangle, and rectangle — the three most frequently needed shapes in everyday calculations. For more complex polygons, you can break them down into triangles and rectangles, calculate each area separately, and sum the results.