Area Calculator – Calculate the Area of Common Shapes
Compute the area of common shapes.
About the Area Calculator
What is the Area Calculator?
An area calculator computes the area of squares, rectangles, triangles, circles, trapezoids and more from your measurements.
Why use this calculator?
Flooring, painting, tiling and gardening all end with an area question. One form covering the common shapes saves the formula lookup.
How to use it
- Choose the shape.
- Enter the dimensions it needs (labels via the form).
- Read the area and, where relevant, the perimeter.
Formula
Standard geometry formulas: e.g. rectangle = l × w, circle = πr².
Angles for the sector are in degrees.
Frequently Asked Questions
How do I convert sq ft to sq m?
1 sq m = 10.7639 sq ft. Divide by 10.7639 to go the other way.
Why is the ellipse formula πab?
An ellipse is a stretched circle: same π factor but with two radii a and b multiplying.
What order of operations does this use?
It follows standard PEMDAS/BODMAS rules: parentheses, exponents, multiplication and division, then addition and subtraction.
How precise are the answers?
The calculator uses double-precision floating-point math (about 15 significant digits) and rounds the display. For exact symbolic results use dedicated algebra software.
Can I enter negative numbers or decimals?
Yes. Negative values, decimals and very large or small numbers are all supported unless a field says otherwise.
What does it mean if I get an error?
Errors usually mean an invalid input, such as division by zero or a negative value where only positives make sense. Check your entries and try again.
Which units should I use?
Use one consistent unit for every input. The result will be in that unit (or its square or cube for area and volume).
How is area different from perimeter?
Perimeter is the distance around a shape; area is the space it covers. Perimeter is measured in units, area in square units.
Does the orientation of the shape matter?
No. Area, perimeter and volume depend only on the dimensions, not on how the shape is rotated or positioned.
Is this calculator free to use?
Yes. Every calculator on this site is completely free, with no hidden fees, no subscriptions and no limits on how many times you can use it.