Vanity Size Calculator — Single & Double Sink Widths, Height & Depth

For a single sink, 24 inches is the smallest standard vanity width. The standard single sink vanity dimensions run 24, 30, 36, 42, and 48 inches wide. Measure your wall, then take the largest standard size that fits: a 36 inch wall takes a 36 inch vanity, while a 50 inch wall takes a 48 inch vanity with 2 inches left over. Keep the sink center at least 15 inches from each side wall, so a centered sink needs a wall at least 30 inches wide (2 × 15). If you have 60 inches of wall or more, consider a double-sink vanity instead of one wide single.

Sink centers on a double vanity should be at least 30 inches apart, matching the 30-inch center-to-center minimum in the plumbing code. The minimum width for double vanity cabinets is 60 inches, which puts the centers exactly 30 inches apart; 66 to 72 inches feels comfortable for two people. On a 72 inch double vanity the centers sit 36 inches apart, leaving 19 inches between the edges of two 17-inch bowls (36 − 17 = 19). With less than 60 inches of wall, choose a single 48-inch vanity instead of squeezing in two sinks.

The standard vanity height is 32 to 36 inches from the finished floor to the top of the countertop. Traditional vanities sit at 30 to 32 inches; the comfort height vanity range is 34 to 36 inches — about kitchen-counter height and the most popular choice for primary bathrooms today. The vanity height for vessel sink setups is lower: choose a 28 to 31 inch cabinet so that after the bowl sits on top, the rim lands at 34 to 36 inches — for example, a 6 inch vessel on a 29 inch cabinet gives a 35 inch rim (29 + 6 = 35). One designer guideline caps the cabinet at 34.5 inch cabinet height for a standard sink, even for tall users. For wheelchair access, the ADA limits the rim to 34 inches maximum.

The standard bathroom vanity depth is 21 inches for the cabinet; the countertop adds about 1 inch, so the finished projection is about 22 inches. Shallow 18-inch cabinets save floor space in tight bathrooms and powder rooms. Whatever depth you choose, keep at least 21 inches of clear floor space in front of the vanity — that is the code minimum. Example: a 60 inch deep room with a 21 inch vanity leaves 39 inches of walkway (60 − 21 = 39), while a 40 inch room with an 18 inch vanity leaves 22 inches (40 − 18 = 22).

IRC section P2705.1 sets three minimums for a lavatory: the sink center to side wall clearance must be at least 15 inches to any side wall or partition; adjacent fixtures need 30 inches center-to-center; and the clearance in front of vanity must be at least 21 inches to any wall, fixture, or door. For comfort, designers commonly target 30 inches of clear space in front — 21 inches is the legal floor, not the comfort target. Use the Clearances mode above to check your measurements against all three numbers.

For a 48 inch vanity, choose a single mirror 42 to 46 inches wide — 2 to 6 inches narrower than the cabinet — inside the 70 to 90 percent band of 33.6 to 43.2 inches. A double vanity gets one mirror per sink: on a 72 inch cabinet, each 36-inch sink section takes a mirror 25.2 to 32.4 inches wide, aligned to the sink centers. Hang the bottom edge 5 to 10 inches above the backsplash. For full mirror rules — hanging height, mantels, leaning and round mirrors — use our mirror size calculator.

Bathroom sink bowls are typically 16 to 20 inches across. To decide how much counter space around a sink you need, aim for at least 3 inches of counter on each side of the bowl; 5 to 6 inches feels comfortable. A 30 inch vanity with an 18 inch bowl leaves 6 inches per side ((30 − 18) / 2 = 6), comfortably in range. A 24 inch vanity with a 20 inch bowl leaves only 2 inches per side and will feel cramped — and a bowl that wide leaves no room for a faucet deck. Use the Sink & counter mode above to check your combination.

This tool sizes the vanity cabinet — width, height, depth, clearances, and mirror pairing. It does not size the mirror itself beyond the pairing band: for hanging height, mantel rules, leaning and round mirrors, see the mirror size calculator. It also does not lay out plumbing rough-in or drain placement — always confirm pipe locations before buying. Note the category boundary: a bathroom vanity follows plumbing code (IRC P2705.1) and sink ergonomics, while a dresser or sideboard follows furniture proportion rules — they are different tools.