Area Calculator
Calculate the area of different shapes like squares, rectangles, circles and triangles.
The result uses the same unit of measurement you entered, squared (e.g., if you typed values in meters, the result is in m²).
The area calculator quickly finds the area of four common shapes: square, rectangle, circle and triangle. Pick the shape, fill in the required measurements, and see the area calculated automatically, using the correct formula for each figure.
How to use
- Choose the shape: square, rectangle, circle or triangle.
- Fill in the measurements requested for that shape, all in the same unit.
- Watch the area update automatically as you type.
Worked example
Say you want to know how much flooring to buy for a rectangular room 4.5 m wide by 6 m long. Choosing the Rectangle shape and entering 4.5 and 6, the calculator multiplies the two values and returns 27 m². Once you know the area, just add roughly a 10% margin for cuts and waste and you have the amount of flooring to buy.
Frequently asked questions
What formulas are used for each shape?
Square: side × side. Rectangle: width × height. Circle: π × radius². Triangle: (base × height) ÷ 2.
Why doesn't the result show a unit like m² or cm²?
Because the calculator works with any unit — the result is always the unit you used in the fields, squared. If you entered the sides in centimeters, the result is in square centimeters.
Which height should I use to calculate a triangle's area?
Use the height relative to the base you chose — the perpendicular distance between the base and the opposite vertex, not the length of one of the triangle's other sides.
How do I calculate the area of an L-shaped room?
Split the space into two rectangles, calculate each area separately, and add the results. This technique of breaking an irregular shape into simple ones works for most real-world spaces.
What is calculating area useful for in practice?
It's essential for buying flooring, paint, carpet or turf, sizing rooms, measuring plots of land, and many renovation and construction projects. Knowing the area avoids buying too much or too little material.
What's the difference between area and perimeter?
Area measures the surface inside a shape (in squared units like m²), while perimeter is the sum of the side lengths — the outline (in linear units like meters). You use area to cover a surface and perimeter to fence it, for example.