How it works
Compute the area of a rectangle, circle, or triangle.
Choose a shape and enter its dimensions. The calculator returns the area using the matching formula.
Formula
Rectangle A = l × w; circle A = πr²; triangle A = ½ × base × height.
l/w/r/b/h- Shape dimensions (length)
Examples
- 5 × 3 rectangleRectangle · length 5 · width 315 square units
Frequently asked questions
Which units does it use?
Any consistent unit. The area is reported in the square of whatever unit you enter.
What about irregular shapes?
Split them into rectangles, triangles, and circles, then sum the areas.
How to read the result
Area measures the two-dimensional surface enclosed by the shape.
Limitations
Three basic shapes only; no polygons or curved irregular regions.
Source: Standard area formulas for rectangle, circle, and triangle.