Width of a Rectangle Calculator

Using the width of a rectangle calculator is easy, with only two steps. Here's how.

• Enter the dimensions that you know of the rectangle.
• Find your rectangle width in the bottom box.
• The calculator is -directional — if you want to work backwards instead, you can change the rectangle's width and see how its other dimensions react.
• And that's it! Now you know how to calculate the width of a rectangle!

Depending on what information you have available, there are many ways to calculate the width of a rectangle.

• If you have the area A and length h, its width w is w = A/h.
• If you have the perimeter P and length h, its width is w = P/2−h.
• If you have the diagonal d and length h, it's width can be found with w = √(d²−h²).
• If the rectangle's length is not known, you'd need to do some algebra with the quadratic equation to solve for the width.

That's a lot of different formulas for the width of a rectangle! It's because there are multiple equations that govern the dimensions of a rectangle. Here they are:

where:

• is the rectangle's width;
• is the rectangle's length;
• is the rectangle's area;
• is the rectangle's perimeter; and
• is the length of the rectangle's diagonal (as described by the Pythagorean theorem).

Here's a neat visual:

If the width of a rectangle calculator isn't quite what you want, try out our other rectangular calculators:

• Area of a rectangle calculator
• Dimensions of a rectangle calculator
• Diagonal of a rectangle calculator
• Rectangle diagonal angle calculator
• Perimeter of a rectangle
• Surface area of a rectangle calculator
• Length of a rectangle calculator
• Length and width of rectangle given area calculator
• Length and width of rectangle given perimeter calculator
• Perimeter of a rectangle with given area
• Rectangle scale factor calculator
• Square feet of a rectangle calculator
• Golden rectangle calculator