About this tool
Calculate the area (and perimeter where defined) of common 2D shapes.
Square a², rectangle a·b, circle πr², triangle ½·b·h, trapezoid ½(a + b)·h, parallelogram b·h, ellipse π·a·b.
Formula: A = πr² · A = a·b · A = ½bh
Example: Shape = Rectangle, Side a / base / semi-axis a = 12 → Area = 90, Perimeter / circumference = 39.
Use the same unit for every length; the area is in that unit squared.
Quick steps
- Enter your values — every field shows its unit.
- Press Calculate (or Try an example to see how it works).
- Read the results and copy them if you need them elsewhere.
The calculation runs in your browser. Nothing you type is sent to 1CLIK.
FAQ
How does the Area Calculator (Square, Rectangle, Circle…) work?
Square a², rectangle a·b, circle πr², triangle ½·b·h, trapezoid ½(a + b)·h, parallelogram b·h, ellipse π·a·b.
What should I keep in mind?
Use the same unit for every length; the area is in that unit squared.
Is my data sent anywhere?
No. The numbers stay on your device; the page only shows the result.