Area Calculator
Please enter valid, positive dimensions.
What Is an Area Calculator?
An area calculator finds the surface area (and perimeter/circumference) of common 2D shapes based on their dimensions. It's useful for home improvement projects, landscaping, flooring, and geometry homework.
Formulas Used
Square: Area = side², Perimeter = 4 × side
Rectangle: Area = length × width, Perimeter = 2(length + width)
Circle: Area = π × radius², Circumference = 2 × π × radius
Triangle: Area = (base × height) ÷ 2
How to Use This Calculator
Select the shape you need from the dropdown, enter the required dimensions, then click "Calculate Area" to see the area and perimeter (or circumference) instantly.
Frequently Asked Questions
What units does this calculator use?
The calculator is unit-agnostic — enter values in feet, meters, inches, or any consistent unit, and the result will be in that same unit squared.
Can I calculate the area of an irregular shape?
No, this calculator supports square, rectangle, circle, and triangle only. Irregular shapes typically need to be broken into these basic shapes and added together.
How do I calculate area for flooring or paint estimates?
Use the rectangle option with your room's length and width to get the total square footage, then add a small buffer (5-10%) for waste when ordering materials.
What's the difference between area and perimeter?
Area measures the space inside a shape (in square units), while perimeter measures the total distance around the outside edge (in linear units).