What is the formula for the area of a rectangle?

Area = width × height. Multiply the two side lengths together.

What's the difference between a rectangle's area and its perimeter?

Area measures the enclosed surface (width × height); perimeter measures the total distance around all four sides.

Is a square just a special rectangle?

Yes — a square is a rectangle where width and height are equal, so its area simplifies to side².

Is this tool free to use?

Yes — completely free, no account needed. Everything is calculated entirely in your browser and never uploaded to a server.

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Rectangle Area Calculator Online

What you can expect

Calculate the area of a rectangle from its width and height with this free online calculator. Enter both sides to get the area instantly, useful for rooms, walls, paint estimates, and geometry homework.

Rectangle Area

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Square Area

Calculate the area of a square from its side length with this free online calculator. Enter one side to get the area using side², useful for tiling, flooring, and geometry homework.

Parallelogram Area

Calculate the area of a parallelogram from its base and height with this free online calculator. Enter the base and vertical height to get the area using base × height for geometry and drafting.

Trapezoid Area

Calculate the area of a trapezoid from its two parallel bases and height with this free online calculator. Uses (a + b) / 2 × height, useful for land plots, roof sections, and geometry homework.

Triangle Area

Calculate the area of a triangle from its base and height with this free online calculator. Enter both values to get the area using ½ × base × height, useful for gables, sails, and geometry homework.

Circle Area

Calculate the area of a circle from its radius with this free online calculator. Enter the radius to get the area using π × r², useful for geometry homework, garden beds, and round tables.

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Frequently asked questions

What is the formula for the area of a rectangle?: Area = width × height. Multiply the two side lengths together.
What's the difference between a rectangle's area and its perimeter?: Area measures the enclosed surface (width × height); perimeter measures the total distance around all four sides.
Is a square just a special rectangle?: Yes — a square is a rectangle where width and height are equal, so its area simplifies to side².
Is this tool free to use?: Yes — completely free, no account needed. Everything is calculated entirely in your browser and never uploaded to a server.

For developers

Use Rectangle Area from Python

Open the Jupyter notebook example to see how to run this tool from the BrushCue Python API, inspect the processing steps, and adapt the workflow for scripts or batch image jobs.

View Python notebook

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