Homeowner’s Guide To Bathroom Sink Dimensions and Sizes

Bathroom sink dimensions fall within standard ranges, but there are no rules. The good news? You can usually find a right-sized sink for any bathroom.

Sink manufacturers offer multiple bathroom sink sizes, so if you have a standard-size bathroom it’s usually easy to find a sink to fit. But what if your bathroom isn’t a standard size? You could have a tiny bathroom nestled into a space that used to be a closet, or an oversized one with a super-long countertop to serve a large family. Can you find a sink to fit?

The answer, of course, is yes. There are practical limitations on depth, and sink width is often constrained by countertop width or code-required bathroom clearances. Length is limited only by the size of the countertop and the design of the vanity

Style is one of the most important variables in determining optimum bathroom sink dimensions. Because undermount and vessel sinks lack rims that take up space on the countertop, they can be wider than top-mounts and often deeper. Special considerations apply to wall-mount and pedestal sinks.

How To Measure a Bathroom Sink

Product descriptions for undermount, vessel and drop-in sinks usually provide the inside dimensions, measured from the inside rim at the top of the sink. This defines the amount of available washing space. The product description for a wall-hung lavatory or pedestal sink, however, usually provides the outside dimensions, which tells you how much room to allow for it.

The length of a sink is the measurement parallel to the back wall, while the width runs perpendicular to the back wall. With an oval sink, the length reflects the longer axis and the width the shorter one. For a round sink, you only need the diameter. Some oval sink product descriptions mention diameters, but that refers to the length and width.

The height and depth of a sink are different measurements. The height is taken on the outside of the sink from top to bottom. The depth is the distance from the overflow hole to the drain opening. If there’s no overflow, depth is measured from the top of the rim to the drain opening.

Common Bathroom Sink Sizes

Standard sink sizes for top-mount and undermount sinks vary according to the shape of the sink. Most are within the following range:

Rectangular and oval

  • Small: From 15 to 20 inches long and nine to 12 inches wide, with a depth between 5-3/4-in. and seven inches.
  • Medium: From 20 to 30 inches long, 19 to 24 inches wide and about seven inches deep.
  • Large: From 30 to 50 inches long, 19 to 24 inches wide and about five inches deep. It’s difficult to fit these larger “trough-style” sinks on a standard countertop; they work best as wall-mounts.


  • Small: From seven to 10 inches in diameter.
  • Medium: From 11 to 15 inches in diameter.
  • Large: From 16 to 20 inches in diameter.

Depth typically varies from five to eight inches.


Pedestal sinks vary in length from 15-1/2-in. to 30-in., although the classic length is between 22 and 28 inches. Sink width can vary, but it’s usually between 17 and 20 inches. Remember, these are outside dimensions.


Although wall-mount sinks can be really long, they are typically 16 to 23 inches long, 15 to 18 inches wide and five to eight inches deep. Wall-mounts are space-savers by design, so it’s possible to find ones less than 10 inches long to fit into a tiny bathroom.


Because they sit on top of the counter, vessel sinks can have wider openings than top-mounts or undermounts. They can be deep too, as long as the countertop is low enough to keep the rim at a usable height.

Typical dimensions for round vessel sinks run 14 to 20 inches in diameter and four to seven inches deep. Rectangular and square ones tend to be shallower, from 15 to 25 inches long and 16 to 20 inches wide.

What Size Sink Do You Need?

When installing a top-mount or undermount sink, you generally need about two inches of space from the front of the countertop to the front of the sink, and at least that much between the back of the sink and the backsplash depending on the faucet.

The space you need along the length of the countertop isn’t as important, but you may be constrained by the framework of the vanity. If you need more sink space on a small countertop, a vessel sink installed with a wall-mount faucet is a great option, because the sink rim can extend all the way to the front and back of the countertop.

When choosing a pedestal or wall-mount sink for a small bathroom, select any one that fits in the available space, provided you allow for code-required clearances. They are 30 inches from the centerline of the sink to the centerline of any adjacent fixture, such as the toilet, and at least 21 inches from the front of the sink to the facing wall.

Chris Deziel
Chris Deziel has been active in the building trades for more than 30 years. He helped build a small city in the Oregon desert from the ground up and helped establish two landscaping companies. He has worked as a carpenter, plumber and furniture refinisher. Deziel has been writing DIY articles since 2010 and has worked as an online consultant, most recently with Home Depot's Pro Referral service. His work has been published on Landlordology, Apartments.com and Hunker. Deziel has also published science content and is an avid musician.