Area Calculator
Calculate areas for rectangles, circles, triangles and other shapes with formulas and square-unit results. Processing takes place locally in your browser.
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What this calculator does
Calculate the area of common two-dimensional shapes with shape-specific inputs and a result expressed in square units.
Worked example
Rectangle: width 8 ft, height 5 ft
Area: 40 ft²
How the calculation works
The selected shape determines the formula. A rectangle uses width × height, a triangle uses base × height ÷ 2, and a circle uses π × radius². Other supported shapes apply their corresponding geometric formula.
When to use it
- Estimate flooring, paint coverage or landscaping area
- Check geometry homework and construction sketches
- Compare material requirements for alternative dimensions
Limits and checks
- All dimensions must use the same unit.
- The result is a mathematical estimate and does not include waste or tolerances.
- Irregular shapes may need to be divided into several regular shapes.
Frequently asked questions
Why is the result in square units?
Area measures a two-dimensional surface, so a length unit is multiplied by another length unit.
Can I mix feet and inches?
Convert every dimension to one unit before calculating, then convert the final area if needed.
How should I calculate an irregular floor plan?
Split it into supported regular shapes, calculate each area in one unit, then add or subtract the sections.
Processing takes place locally in your browser.