Geometry & Shapes
Area Calculator
Area — it applies the matching area formula for the shape you pick — rectangle, triangle, circle and more. This page runs that same calculation on your numbers, in your browser: no signup, no uploads, nothing stored.
From your shapes, Area Calculator computes the area via the matching area formula for the shape. No accounts, no uploads — just an instant way to find the area of a shape.
About this calculator
It applies the matching area formula for the shape you pick — rectangle, triangle, circle and more. It matters whenever a shape has to be measured, cut, covered or compared and the geometry has to be right first. Here is the calculation on real numbers: Area of a rectangle 8 m × 5 m = 8 × 5 = 40 m² . The tool uses the matching formula for circles, triangles and other shapes. For your own figures, use the calculator above — same method, your inputs, computed on-device.
How to use
- Type one shape per line, such as "rect, 10, 5".
- Use the documented keywords: rect, square, circle, or triangle.
- Press Calculate to total the areas.
- Review the per-shape breakdown below the total.
Why use Area Calculator
Fast
Calculations run in your browser. No round trip to a server.
Private
Your inputs never leave your device. Nothing is uploaded.
Free
No signup, no paywall, no ads-in-results, no watermarks.
Accurate
Uses standard formulas where applicable; check critical results before relying on them.
Mobile-ready
Optimised for phones, tablets, and desktops alike.
Transparent
Honest disclaimers wherever browser limits or regional rules apply.
Common uses
Use it for craft and woodworking projects
Use it for flooring and tiling estimates
Use it for school and college geometry
Use it for sign and panel sizing
Use it when sizing a room or plot of land
Use it when checking a homework answer
Technical notes
Area Calculator applies the matching area formula for the shape you pick — rectangle, triangle, circle and more.
Results assume exact, idealised shapes; real-world measurement error is not included.
All arithmetic runs in your browser using double-precision floating point, so extreme inputs may show tiny rounding differences.
FAQ
Which shapes can I list?
You can list rectangles, squares, circles, and triangles, each with its required dimensions on its own line.
What happens if a line is invalid?
The calculator stops and tells you which line is wrong rather than quietly adding a partial or incorrect total.
Can I mix different shapes in one calculation?
Yes. Each line is calculated on its own and the valid areas are added into a single total.
Does the Area Calculator send my data to a server?
No. The Area Calculator runs entirely in your browser, so nothing you enter is uploaded, stored, or shared.
Worked example
Area of a rectangle 8 m × 5 m = 8 × 5 = 40 m². The tool uses the matching formula for circles, triangles and other shapes.