Bathroom Layouts by Size: What Fits at Every Footprint

Why footprint decides the layout before style does

Every bathroom layout is really a packing problem: fixtures of fixed sizes, plus the legally required clear space around each one, arranged inside a fixed rectangle. A standard tub is 60 by 30 inches. A toilet needs 15 inches from its centerline to anything beside it and 21 inches of open floor in front, per the International Residential Code. A shower interior can be no smaller than 30 by 30 inches. Those numbers do not negotiate, which is why two bathrooms of the same size almost always end up with one of the same two or three workable layouts.

This article is the by-the-numbers version: footprint by footprint, what fits and what does not. For the design principles behind those choices — wet walls, sight lines, door swings, and how to weigh one layout against another — see our guide to choosing a bathroom layout, which owns that territory.

One prerequisite matters more than anything below: accurate measurements. An inch of error at a tub wall is the difference between a standard 60-inch tub and a custom order. Our walkthrough on measuring your bathroom covers how to do it right before you start sketching.

The clearance numbers that rule every footprint

Two sets of numbers govern bathroom layouts. Code minimums come from the International Residential Code (IRC) as adopted by Idaho and Treasure Valley jurisdictions — these are legal floors, not comfort targets. Recommended clearances come from the National Kitchen & Bath Association (NKBA), whose planning guidelines describe what actually feels comfortable to use.

The gap between the two is the story of most layout decisions. A toilet 15 inches from the vanity is legal; at 18 inches it stops feeling pinched. Twenty-one inches in front of a vanity passes inspection; 30 inches lets two people pass each other. When a footprint is quoted as "fitting" something below, it means at code clearances — comfort is called out separately where it changes the verdict.

• Toilet: 15 in. minimum from centerline to any wall or fixture (IRC); NKBA recommends 18 in.
• Clear floor in front of toilet, tub, and sink: 21 in. minimum (IRC); NKBA recommends 30 in.
• Shower interior: 30 x 30 in. minimum finished dimensions (IRC); NKBA recommends 36 x 36 in.
• Standard alcove tub: 60 x 30–32 in. — the fixed block most layouts are built around.
• Single vanity: 24–48 in. wide; a true double vanity starts at 60 in. and is comfortable at 72 in.
• Ceiling height: 6 ft. 8 in. minimum over fixtures and in the shower (IRC).

What fits at each footprint: the reference table

The table below is the summary version of this whole article. Square footage alone is misleading — an 8x10 room and a 5x16 room are both 80 square feet, but only one of them takes a double vanity — so proportions are baked into each verdict.

Small footprints: 5x8 and 6x9

The 5x8 bathroom — 40 square feet — is the most common full-bath footprint in American housing, and it is common precisely because it is the minimum rectangle that fits a tub, toilet, and sink at code clearances. There is essentially one layout: the 60-inch tub spans the 5-foot end wall, and the toilet and vanity line up along one 8-foot wall, sharing a single wet wall. Everything worth knowing about working within it — including the tub-to-shower swap that modernizes most of them — lives in our dedicated 5x8 bathroom layout guide.

At 6x9, the extra foot in each direction changes feel more than function. The program is still tub-or-shower, toilet, single vanity — but the vanity can grow to 48 inches, the door swing stops grazing the toilet, and a 48-inch walk-in shower becomes an option in place of the tub. NKBA-comfortable clearances, not just code-legal ones, start being achievable here.

If you are trying to make a small footprint live larger without moving walls, that is a design problem more than a dimensional one — our guide to small bathroom remodel ideas covers the visual and storage strategies that do the heavy lifting.

The middle: 8x10 and the double-vanity threshold

Eighty square feet is where layouts stop being predetermined and start involving real choices. An 8x10 bathroom fits a 60-inch double vanity along one 10-foot wall with room to spare, or a separate tub and shower along it — but fitting both a double vanity and separate bathing fixtures at this size means compromising one of them, usually the shower shrinking to its 36-inch floor.

The either/or math, the wet-wall economics, and the three layouts that actually work at this size get full treatment in our 8x10 bathroom layout guide. The one-line version: pick the single upgrade that matters most to your household — second sink or second bathing fixture — and give it the long wall.

Primary-bath footprints: 8x14 and 9x12

Above 100 square feet, the packing problem relaxes and the full program fits: separate tub, separate shower, double vanity, and honest circulation space. The two classic shapes solve it differently. The long 8x14 rectangle lines the wet functions along one 14-foot wall — tub, then shower, sharing plumbing — with a 72-inch double vanity opposite and the toilet tucked at one end, often behind a partition or pocket door as a water closet.

The squarer 9x12 spreads the same program around the perimeter and tends to feel more open for the same area. It is also the shape where a freestanding or corner tub earns its floor space, since the room can afford to give the tub air on two sides instead of jamming it into a run.

At these sizes the constraint usually stops being the room and becomes the house: whether the footprint exists at all, or has to be borrowed from a closet or adjacent bedroom. If that is the fork you are at, should I expand my bathroom walks through when taking space is worth it and what it costs. And if aging-in-place is part of the plan, the clearances get more generous still — our bathroom ADA dimensions reference has the full number set.

The economics hiding inside the layout

Two bathrooms of identical size can differ meaningfully in cost purely on plumbing arrangement. Keeping the toilet, sink, and tub or shower on one or two shared wet walls means shorter supply and drain runs and less slab or joist work; relocating a fixture to a new wall typically runs roughly $500 to $1,500 per fixture in accessible framing, per Angi’s cost data, and more when concrete or joist direction gets involved.

This is why the layouts above lean on shared wet walls, and why the cheapest good remodel usually keeps fixtures where they are and upgrades what they are. The layout-principles guide covers when moving fixtures is worth it; as a rule of thumb, move plumbing to fix a genuine functional problem, not to chase a floor plan that is only marginally better.