The Area & Perimeter Calculator finds the area and perimeter/circumference for common 2D shapes. Choose a shape, enter the dimensions, and see the results instantly. Perfect for homework, design, DIY projects, and classroom demonstrations.
What does the calculator do?
- Supports multiple shapes: rectangle, triangle, circle, parallelogram, trapezoid.
- Flexible inputs: e.g., radius or diameter for circles; base/height for area and sides for triangle perimeter.
- Units-aware outputs: Enter your unit (cm, m, in) and see area in square units and perimeter in units.
- Copy results: One click for worksheets, notes, or design briefs.
Worked examples
Rectangle, w=5 cm, h=8 cm → Area = 40 cm², Perimeter = 26 cm
Triangle, base=10 m, height=6 m; sides 7, 10, 8 → Area = 30 m², Perimeter = 25 m
Circle, radius=3 in → Area ≈ 28.274 in², Circumference ≈ 18.850 in
Why is it important?
- In school: Reinforces formula use and unit reasoning.
- Real life: Paint/tiling estimates, fencing lengths, garden layouts, fabric cutting.
- STEM: Foundation for geometry, trigonometry, and modelling.
Frequently Asked Questions
Q1: Which units can I use?
Any (cm, m, in, ft). The calculator treats the unit label as text and formats outputs accordingly.
Q2: Do I need all triangle sides?
Not for area — base and height are enough. Provide 3 sides only if you want perimeter too.
Q3: Can I enter decimals?
Yes.