Measure the wall the vanity goes on and say what is at each end. You get the widest vanity that fits, single or double, where it sits, where the sink lands, and the floor it leaves in front.
Vanity size
A 36″ vanity, 1¾″ from the side wallits sink 20″ from the wall · its end 21¾″ from the toilet’s middle · the NKBA’s recommended room
Quick answer: a vanity’s sink must sit at least 15″ from a side wall (the plumbing code; the NKBA recommends 20″), and a toilet’s middle 15″ from the vanity (NKBA: 18″). So from a side wall to a toilet’s middle, a 24″ vanity needs 42¼″ of wall and a 36″ one 51½″ (56¼″ with the NKBA’s room). Between two walls, a 60″ double needs 65½″. Leave 21″ of floor in front (the NKBA recommends 30″).
How to use the vanity size finder
- Say what is at each end of the vanity’s wall: a side wall, a toilet, or nothing.
- Measure the wall: from the side wall to the other wall, or to the middle of the toilet.
- Measure the room in front, to the opposite wall or tub, if you want the floor checked.
- Read the widest vanity that fits, how far from the wall it goes and where the sink lands.
The rules behind the numbers
The sink and the side wall
The NKBA’s Bath Planning Guidelines: “The distance from the centerline of the lavatory to the sidewall/tall obstacle should be at least 20″.” The plumbing code: “The minimum distance from the centerline of the lavatory to a wall is 15″” (IPC 405.3.1). That is why a 24″ vanity pushed into a corner, its sink 12¼″ from the wall, fails the code: it needs a 2¾″ gap.
Two sinks
The NKBA: “The distance between the centerlines of two lavatories should be at least 36″”; the code: 30″. Kohler’s 60″ Chesil double vanity puts its sinks 35 7⁄16″ apart and 12½″ from each end, so it meets the code but not the NKBA’s 36″, and needs 2½″ from a side wall.
The toilet beside it
The NKBA: “The distance from the centerline of toilet … to any bath fixture, wall or other obstacle should be at least 18″”; the code: 15″ (IRC R307.1, IPC 405.3.1). Measure the wall to the toilet’s middle and the calculator keeps the vanity’s end that far away.
The floor in front
The NKBA: “a clear floor space of at least 30″ from the front edge of all fixtures … to any opposite bath fixture, wall or obstacle”; the code: 21″ in front of a lavatory. Kohler’s Chesil tops are up to 22⅞″ deep.
How much wall each vanity needs
| Vanity (Kohler Chesil) | Between two walls | Side wall to a toilet’s middle |
|---|---|---|
| 24″ | 30″ (NKBA 40″) | 42¼″ (NKBA 50¼″) |
| 30″ | 30½″ (NKBA 40″) | 45½″ (NKBA 53¼″) |
| 36″ | 36½″ (NKBA 40″) | 51½″ (NKBA 56¼″) |
| 48″ | 48½″ (NKBA 48½″) | 63½″ (NKBA 66½″) |
| 60″ double | 65½″ (NKBA: never) | 78″ (NKBA: never) |
The code’s minimum first, the NKBA’s recommended room in brackets. “Never”: the 60″ double’s sinks are 35 7⁄16″ apart, under the NKBA’s 36″.
Three worked examples
60″ from a side wall to the toilet’s middle. A 36″ vanity, 1¾″ from the wall: its sink 20″ from the wall and its end 21¾″ from the toilet, all the NKBA recommends.
A tight 48″ powder room wall. Only a 30″ vanity at the code’s minimum: its sink 15¼″ from the wall, its end 17½″ from the toilet.
72″ between two walls. A 48″ vanity keeps every NKBA distance; the 60″ double fits only at the code’s minimum.
Common vanity sizing mistakes
- Measuring to the toilet’s side, not its middle. Every rule is to the toilet’s centreline.
- A small vanity jammed into a corner. Its sink ends up under 15″ from the wall.
- A double vanity on a short wall. Two sinks need 30″ between their middles (NKBA: 36″).
- Forgetting the floor in front. A deep vanity in a narrow bathroom leaves less than 21″ to stand in.
Next, how high it stands and the mirror over it: the free vanity height and mirror size calculator. The medicine cabinet size calculator sizes a cabinet over it, and the free 2D room planner lays out the whole bathroom.
Its height and mirrorRead next
Vanity size questions
What are the standard bathroom vanity sizes?
Kohler’s Chesil vanities, for one maker’s line: 24, 30, 36 and 48″ wide with one sink and 60″ with two, each top ½″ wider than its name and up to 22⅞″ deep.
What are bathroom vanity dimensions?
The width (24–60″ and more), the depth (Kohler’s Chesil tops: up to 22⅞″) and the height (the vanity height calculator covers that). What decides the width is the wall: the sink’s middle 15″ from a side wall (NKBA: 20″) and a toilet’s middle 15″ from the vanity (NKBA: 18″).
What size vanity for my bathroom?
The widest that keeps those distances on your wall. From a side wall to a toilet’s middle, 60″ of wall takes a 36″ vanity with the NKBA’s room, and 48″ takes a 30″ one at the code’s minimum.
What is the standard vanity depth?
Kohler’s Chesil vanity tops are up to 22⅞″ deep. With 21″ of floor needed in front (30″ recommended), the bathroom must be at least 43⅞″ from the vanity’s wall to what faces it.
What is the double vanity size?
60″ and up. Kohler’s 60″ double puts its sinks 35 7⁄16″ apart, over the code’s 30″; the NKBA recommends 36″. Between two walls it needs 65½″, so its sinks stay 15″ from each wall.
What is the standard bathroom vanity width?
24, 30, 36 or 48″ for one sink. The table above gives the wall each one needs, between two walls or from a side wall to a toilet.