In a long, narrow bathroom, line the fixtures up along one long wall and use the floor in front of them as the walkway. The code wants 21 in of clear floor in front of a toilet or a sink, so a toilet about 30 in deep needs a room at least 51 in wide to sit on the long wall. That’s why 5 ft is the usual narrow width; at 4 ft the toilet has to go on an end wall.
How wide must a narrow bathroom be?
| Room width | What fits on a long wall | What it means |
|---|---|---|
| 4 ft (48 in) | A vanity (21 in deep + 21 in clear = 42 in) | The toilet goes on an end wall, facing down the room; a shower fits across an end |
| 5 ft (60 in) | A toilet (30 + 21 = 51 in) or a vanity | Everything on one long wall, a 60 in tub or shower across an end |
| 6 ft (72 in) | A vanity on one long wall and a tub on the other | 72 − 21 − 30 = 21 in between them, the code minimum in front of the vanity |
Depths: an elongated toilet about 30 in from the wall, a standard vanity 21 in, a 60 in alcove tub 30 in. The code’s clear floor: 21 in in front of a toilet or sink, 24 in in front of a shower (IRC R307.1). The planner also checks there’s a way through from the door to each fixture.
Six long narrow layouts, drawn to scale
The dashed boxes are the clear spaces in front of the fixtures, and the dark bar in the split plan is a partition wall. Open any plan in the layout planner and change it to your room.
- Clear in front of the vanity: 39 in
- Sink centerline to the side: 21 in
- Toilet centerline to the side: 21 in
- Clear in front of the toilet: 30 in
Everything on one long wall
The classic: a 36 in vanity by the door, the toilet in the middle of the same wall, 21 in from the vanity and 30 in from the tub, and the tub across the far end. The other long wall stays clear, and every roomier designer number is met.
- Good: one plumbing wall and a straight walkway.
- Watch for: the door in the end wall, not the long wall, so it doesn’t swing across the walkway.
- Clear in front of the shower: 88 in
- Toilet centerline to the side: 18 in
- Clear in front of the toilet: 30 in
- Clear in front of the vanity: 39 in
- Sink centerline to the side: 34 in
Shower across the end
Swap the tub for a 60 × 32 in shower base and the walkway runs straight into it, with 88 in of floor in front of the shower. The toilet sits 18 in from the shower, then a 36 in vanity, their centers 36 in apart. More plans at this size: 5x10 bathroom layouts.
- Good: the shower is the first thing you walk toward, not the toilet.
- Watch for: a 32 in deep base is under the NKBA’s 36 in; a 60 × 36 in one fits too.
- Toilet centerline to the side: 21 in
- Clear in front of the toilet: 30 in
- Clear in front of the vanity: 51 in
- Sink centerline to the side: 60 in
Toilet at the far end
At 6 ft wide the fixtures can use both long walls. The toilet faces down the room from the far end wall, 21 in from the side wall and 21 in from the tub, which runs along one long wall. A 48 in vanity takes the other long wall, with 51 in of floor in front of it. More at this size: 6x12 bathroom layouts.
- Good: the vanity wall is long enough for a 60 in double vanity too.
- Watch for: the toilet faces the door; some people prefer it out of the line of sight.
- Toilet centerline to the side: 21 in
- Clear in front of the toilet: 36 in
- Clear in front of the vanity: 51 in
- Sink centerline to the side: 36 in
Split: vanity in front, toilet and tub behind
A partition wall halfway down the room leaves a 30 in opening for a pocket door. The 48 in vanity stays by the entrance, and the toilet and the tub go behind the partition, so one person can use the sink while someone else bathes.
- Good: a long room becomes two useful ones.
- Watch for: plan a light and an exhaust fan behind the partition too.
- Clear in front of the vanity: 39 in
- Sink centerline to the side: 60 in
- Toilet centerline to the side: 27 in
- Clear in front of the toilet: 30 in
Door in the long wall
When the door has to be in a long wall, as in many en suites, a pocket door keeps its swing out of the walkway. The vanity and the toilet face the door from the opposite wall, 27 in apart from the toilet’s centerline to the vanity, and the tub fills one end. More at this size: 5x12 bathroom layouts.
- Good: every roomier designer number is met.
- Watch for: a pocket door needs a wall with no pipes or wires in the pocket.
- Clear in front of the shower: 54 in
- Clear in front of the vanity: 27 in
- Sink centerline to the side: 16 in
- Toilet centerline to the side: 24 in
- Clear in front of the toilet: 26 in
Very narrow: 4 ft wide
At 48 in the toilet can’t sit on a long wall, so it goes on the end wall, 24 in from each side. A 48 × 36 in shower fills the other end, a 24 in vanity takes the long wall between them with 27 in in front of it, and a pocket door opens in the long wall.
- Good: a full 3/4 bath in 40 sq ft of a narrow space.
- Watch for: no tub fits: a 60 in tub needs a 5 ft wall.
Making a narrow room work
- Door on an end wall. A door in a long wall swings across the walkway; at the end it opens into the room’s length. If it has to be in a long wall, use a pocket door.
- One plumbing wall. Lining the fixtures up on one wall keeps the plumbing together and leaves the other wall for storage or a mirror.
- A shallower vanity. An 18 in deep vanity (Kohler Hearthaven: 18-1/16 in) gives back 3 in of walkway compared with a standard 21 in one. Vanity sizes in detail: bathroom vanity sizes.
- The tub or shower across the far end. It closes the view down the room and keeps wet floor away from the door.
Questions people ask
How narrow can a bathroom be?
A full or 3/4 bath can be 4 ft wide with the toilet on an end wall and a shower across the other end. A half bath can be 2 ft 6 in wide with the toilet and the sink facing each other; see half bath dimensions.
Where should the toilet go in a narrow bathroom?
On a long wall if the room is at least 51 in wide, so it has 21 in of clear floor in front; otherwise on an end wall, facing down the room.
Where should the door go in a long narrow bathroom?
In an end wall, so it swings along the room instead of across the walkway. In a long wall, a pocket door works best.
Can a long narrow bathroom have a tub?
Yes, if it’s at least 5 ft wide: a 60 in tub fits across the end. At 4 ft, use a shower instead.
Sources
- 2021 International Residential Code, chapter 3 (R307.1 fixture clearances, R305.1 ceiling height) and chapter 27 (P2705.1 fixture spacing, P2708.1 showers), read in Colorado’s adoption without amendments on UpCodes
- NKBA’s free bath planning guidelines: the roomier spacing (18 in beside a toilet, 20 in beside a sink, 36 in between two sinks, 30 in in front of each fixture, a 36 × 36 in shower, a 32 in door opening, a 36 × 66 in toilet compartment). Its newer, paid editions change some numbers.
- Kohler Underscore alcove tubs, 60 × 30 in and 60 × 32 in spec sheets
- Kohler Hearthaven 36 in vanity spec sheet: 18-1/16 in deep
- Toilet depths from the wall: Kohler Cimarron round and elongated spec sheets
Checked October 19, 2026. All plans were drawn and checked with the BathDraft layout planner; centimeters are converted from inches.