Area Calculator
Result
Area Calculator Popular The Area Calculator finds the area of common shapes — rectangle, square, triangle, circle, trapezoid, parallelogram, and ellipse — from their dimensions. The formulas used are: Rectangle: l×w. Square: s². Triangle: ½bh. Circle: πr² — free online calculator.
Formula
- Common-shape area calculator. This page documents the calculation model and provides an educational worked example.
- The main inputs are Length, Width. Enter them in the units and format shown in the calculator.
- Keep comparable quantities in compatible units whenever the formula combines or compares them.
- Changing any input above recalculates the result with the same calculation engine used by this page.
Example: Area
- Length: 10
- Width: 5
A rectangle 8 by 5 has area 40; a circle of radius 3 has area 9π≈28.27.
Sample result: Calculating…
Frequently asked questions
What does the Area calculate?
Choose the formula matching the shape and use compatible length units.
Which values should I enter?
Enter Length, Width using the units and format shown beside each field.
What formula does this calculator use?
The calculator uses the following relationship: Rectangle A=lw; Square A=s²; Triangle A=½bh; Circle A=πr²; Trapezoid A=(a+b)h/2; Parallelogram A=bh; Ellipse A=πab.
Why might my result differ from another source?
Results can differ when another source uses different units, rounding rules, conventions or assumptions. Compare the inputs and definitions before comparing results.
Does the result update automatically?
Yes. Changing an input updates the result using the same calculation engine shown on this page.