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Rectangle Area Calculator

120
square units (area)
44
Perimeter
15.6205
Diagonal

Calculate the area of a rectangle by entering its length and width. Area equals length multiplied by width, so a room that is 12 by 10 has an area of 120 square units. This calculator also returns the perimeter, which is two times the sum of length and width, and the diagonal, found with the Pythagorean theorem across the two sides. Rectangle area is one of the most used measurements in daily life: flooring, wallpaper, lawn seed, fabric, tiling and packaging all depend on it. Enter your numbers in any consistent unit and the area comes back in that unit squared, so meters give square meters. There is no rounding trickery because everything is computed locally in your browser at full floating point precision, and you can copy the area result instantly with the copy button for use elsewhere.

How to use Rectangle Area Calculator

  1. Enter the length.
  2. Enter the width.
  3. Read the area and perimeter.

Frequently asked questions

How is the area of a rectangle found?

Multiply the length by the width, so a 5 by 3 rectangle has an area of 15.

How is the perimeter calculated?

The perimeter is twice the length plus twice the width, the total distance around the rectangle.

Do the length and width use the same unit?

Yes. Use the same unit for both, and the area comes out in that unit squared.

What is Rectangle Area Calculator?

Calculate the area of a rectangle by entering its length and width. Area equals length multiplied by width, so a room that is 12 by 10 has an area of 120 square units.

Is Rectangle Area Calculator free to use?

Yes. Rectangle Area Calculator is completely free, with no sign-up and no usage limits.

Does Rectangle Area Calculator work in a web browser?

Yes. Rectangle Area Calculator runs in any modern web browser. There is nothing to download or install.

Is my data private with Rectangle Area Calculator?

Yes. Rectangle Area Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.