The formula
How it works
Find the area of a rectangle, triangle, circle, trapezoid or parallelogram. Pick a shape, enter its dimensions, and the calculator applies the right formula and returns the area in square units.
FAQ
What units does the area come in?
Whatever units you enter, squared. If you measure in metres, the area is in square metres; in feet, square feet. Just keep every dimension in the same unit.
How do I find the area of an odd shape?
Break it into rectangles, triangles and circle segments, find each area, and add them up. Most complex outlines can be split into these basic shapes.
How do I calculate the area of a square?
A square is just a rectangle with equal sides, so pick the rectangle shape and enter the same value for length and width. The area is that side length squared.
What is the difference between area and perimeter?
Area measures the surface enclosed by a shape, in square units, while perimeter measures the distance around its edge, in linear units. They answer different questions — how much surface to cover versus how much fencing or trim to buy.
How do I convert the area to a different unit?
Multiply by the appropriate conversion factor squared, since area scales with the square of length. For example, to go from square feet to square metres, multiply by about 0.0929 (the conversion factor for feet to metres, squared).
Is area the same as volume?
No — area is a two-dimensional measure of a flat surface, while volume measures the three-dimensional space a solid occupies. You would multiply an area by a depth or height to get a volume, such as for concrete or soil.
Should I add extra material beyond the calculated area?
For real projects like flooring, turf or paint, it is common to add 5–10% on top of the raw area to allow for cuts, waste and pattern matching. The calculator gives the exact geometric area; buffer amounts are a separate practical decision.
About the area calculator
This calculator finds the area of the most common flat shapes: rectangles, triangles, circles, trapezoids and parallelograms. Area measures how much surface a shape covers, and it turns up constantly — in flooring, painting, gardening, land and design. Each shape has its own short formula, and this tool picks the right one for you, so you only need to know which shape you have and its measurements.
How to use it
Choose the shape from the menu, then fill in the dimensions it asks for. A rectangle needs a length and width, a triangle a base and height, a circle just a radius, and a trapezoid two parallel sides and the height between them. For example, a rectangle 5 by 3 has an area of 15, and a circle of radius 5 has an area of about 78.5. Keep all measurements in the same unit and the area comes out in that unit squared.
The formula
Each shape uses its own rule. A rectangle is length times width, ; a triangle is half the base times the height, ; a circle is ; a parallelogram is base times height; and a trapezoid is the average of its two parallel sides times the height, . All of them can be understood as ways of counting the unit squares that fit inside the shape.
Where it is used
Area calculations are everywhere in daily life and work. You use them to buy the right amount of carpet, turf, paint or fabric, to price land and floor space, and to work out coverage for fertiliser or seed. Builders, designers, farmers and students all rely on these formulas, and combining them lets you measure almost any real-world surface by splitting it into simple shapes.