Bathroom Vanity Calculator

How to use this calculator

Enter the width of wall space available for the vanity, in feet, and choose a single or double sink. Measure between the two walls, doors, or fixtures that bound the vanity, not the whole bathroom wall. The result shows the range of vanity widths that fit, or tells you when the space is too narrow.

How this is calculated

Building code (the International Residential Code) requires the center of a sink to be at least 15 inches from a side wall and at least 30 inches from the next sink. That makes the minimum width 30 inches for a single sink (15 + 15) and 60 inches for a double (15 + 30 + 15). The calculator also allows roughly 3 inches of clearance on each side of the vanity to a wall or fixture.

Example

With 8 feet (96 inches) of available wall, a single vanity can be anywhere from 30 to 90 inches wide, and a double vanity from 60 to 90 inches. If you have exactly 30 inches available, a 30-inch single vanity is a tight fit, and the calculator says so, since there is less than 3 inches of clearance on each side. With less than 30 inches, it reports that the space is too narrow.

Comfort sizing

For a single vanity, 30–36 inches is a comfortable everyday width. For a double vanity, 72–84 inches gives each person real elbow room. Vanities are commonly sold in standard widths such as 24, 30, 36, 48, 60, and 72 inches, so choose the largest standard size that fits.

Before you order

Width is only one measurement. Also check the clear floor space in front of the vanity (the building code requires at least 21 inches, and NKBA recommends 30 inches for comfort), the vanity depth and height, and where the plumbing comes through the wall. Moving the drain and supply lines adds cost, so pick a vanity that lines up with your existing plumbing where you can.

Planning estimate only — always confirm plumbing rough-in locations before ordering a vanity.