Reference · US standards
Sink Base Cabinet Dimensions
US kitchen sink bases are standardized: 24 in deep, 34.5 in tall, in nominal widths of 24 to 36 in. Vanities run 18-21 in deep and 30-36 in tall. Interior width loses about 1.5 in in frameless construction and 2-3 in at a face-frame opening; per-door openings on double-door bases run 13-16 in.
| Cabinet | Nominal width | Depth | Height | Inside: what to expect |
|---|---|---|---|---|
| Kitchen sink base | 24 in | 24 in | 34.5 in | About 22.5 in interior width frameless; 20 - 21 in frame opening face-frame; single door opening about 20 in |
| Kitchen sink base | 30 in | 24 in | 34.5 in | About 28.5 in frameless; 26 - 27 in face-frame opening; doors usually split, each about 13 in clear |
| Kitchen sink base | 33 in | 24 in | 34.5 in | About 31.5 in frameless; double doors, per-door opening 13.5 - 15 in; stile common |
| Kitchen sink base | 36 in | 24 in | 34.5 in | About 34.5 in frameless; double doors, per-door opening 14 - 16 in; stile very common |
| Bathroom vanity | 24 in | 18 - 21 in | 30 - 36 in | About 22 in interior width; usable depth 15 - 18 in after the back rail; bends often 10 - 14 in |
| Bathroom vanity | 30 in | 18 - 21 in | 30 - 36 in | About 28 in interior; single or split doors; drawer banks reduce the sink bay on some models |
| Bathroom vanity | 36 in | 18 - 21 in | 30 - 36 in | About 34 in interior; offset-sink models put the full bay on one side |
| Laundry / utility base | 24 - 30 in | 24 - 26 in | 34 - 36 in | Deepest class; expect standpipes and hoses at the back wall claiming 2 - 3 in of depth |
Figures are common US manufacturing conventions; custom and imported cabinets vary. Your inside tape measurement always overrides the table.
Face-frame vs frameless: where the inches go
Face-frame cabinets (the traditional US style) put a hardwood frame around the opening: nominal 30 becomes a 26-to-27-in frame opening, and euro hinges intrude further at door level. Frameless (full-access) construction loses only the side-panel thickness, about 0.75 in per side. This is why two "30-inch cabinets" can differ by 3 in of real pass-through.
What "sink base" changes inside
A sink base is a standard base shell with the interior gutted for plumbing: false drawer front on top, no shelf, open bay to the floor. Usable height runs from the floor to the sink bowl or trap, typically 16 to 22 in in kitchens and 10 to 16 in in vanities, which is the number the fit checker asks for.
Common questions
How much interior width does a face-frame cabinet lose?
Typically 2 to 3 in versus the nominal size at the frame opening, and euro hinges can intrude another 2 in at door level. Frameless (full-access) cabinets lose only the panel thickness, about 1.5 in total.
Are sink bases different from regular base cabinets?
Same shell, different interior: sink bases have a false drawer front, no shelf, and a full-height open bay for plumbing. Usable height inside runs to the sink bowl or trap, not the countertop.
What sizes do vanities come in?
Common single-sink vanities are 24, 30 and 36 in wide, 18 to 21 in deep, 30 to 36 in tall. Interior depth after the back rail commonly nets 16 to 19 in.