What is a bathroom layout calculator?

A bathroom layout calculator is an interactive planning tool that lets you enter your room size, place fixtures like toilets, vanities, tubs and showers, and automatically checks clearances and circulation space against common design guidelines.

What is the minimum space in front of a toilet?

A common guideline is at least 21 in (53 cm) clear in front of the toilet and 15 in (38 cm) from the centerline of the toilet to any side wall or obstruction. Many designers prefer 30 in (76 cm) in front for comfort.

What is a comfortable bathroom aisle width?

For a single user, 30–32 in (76–81 cm) can work, but 36 in (91 cm) or more feels much more comfortable and is better for two people passing each other.

Can this calculator design ADA or fully accessible bathrooms?

This calculator uses general best‑practice clearances and is not a substitute for ADA, local building codes, or professional design. For accessible bathrooms, always follow the official standards in your jurisdiction and consult a qualified designer or code official.

How accurate is the scale in the bathroom layout canvas?

The canvas uses a simple linear scale based on your room dimensions so that 1 grid square equals 6 inches (15 cm) by default. This is accurate enough for planning and comparing options, but you should always verify final dimensions on site before construction.

Bathroom Layout Calculator

Plan your bathroom floor plan, place fixtures on a scaled canvas, and instantly check clearances and circulation space before you build or remodel.

Units

Room length

ft in

Room width

ft in

Tip: Start with a simple rectangle. You can still explore fixture sizes, clearances, and aisle widths even for more complex bathrooms.

Scaled Floor Plan

Scale: 1 grid = 6 in

Drag fixtures on the canvas. The grid and scale update automatically when you change room size.

Add Fixture

Fixture type

Width in

Depth in

Selected Fixture

Click a fixture on the canvas to edit or delete it.

Clearance Rules

Toilet: ≥ 15" from centerline to side wall, ≥ 21" clear in front.
Vanity: ≥ 21" clear in front.
Tub/Shower: ≥ 24" clear in front recommended.
Aisle width: Aim for ≥ 32" (36"+ preferred).

Clearance Warnings

No issues detected yet. Add and move fixtures to see clearance checks.

Layout Summary

Room size:

Total fixtures: 0

Approx. open floor area: –

Open floor area is an estimate based on fixture footprints; always verify on site.

How this bathroom layout calculator works

This tool is a lightweight alternative to heavy 3D bathroom planners. It focuses on what matters most early in design: room size, fixture sizes, and clearances. You get a scaled 2D canvas, drag-and-drop fixtures, and instant feedback when something is too tight.

1. Room dimensions and scale

Enter your bathroom length and width in either feet/inches or metric. The calculator converts everything to a single internal unit (inches or centimeters) and chooses a scale so the room fits comfortably on the canvas.

Scale logic (imperial example)

If L and W are room dimensions in inches and C is the canvas size in pixels:

\[ \text{scale} = \frac{C - 2 \cdot \text{margin}}{\max(L, W)} \]

Each grid line is drawn every 6 inches, so you can visually count tiles and clearances.

2. Fixture defaults and sizes

When you choose a fixture type, the calculator suggests typical dimensions you can override:

Toilet: ~30" deep × 20" wide (76 × 51 cm)
Single vanity: ~24–36" wide × 21" deep (61–91 × 53 cm)
Standard tub: ~60" long × 30" wide (152 × 76 cm)
Shower: minimum ~32" × 32" (81 × 81 cm), 36" × 36" or larger is more comfortable

3. Clearance checks and rules of thumb

As you drag fixtures, the calculator checks their positions against simple clearance rules derived from common residential design guidelines. These are not a substitute for your local building code, but they are a solid starting point.

Toilet side clearance: centerline ≥ 15" from side wall or obstruction.
Toilet front clearance: ≥ 21" clear in front (30"+ preferred).
Vanity front clearance: ≥ 21" clear in front.
Tub/shower front clearance: ≥ 24" clear in front.
Aisle width: aim for ≥ 32" where people walk; 36–42" feels generous.

When a rule is violated, you’ll see a warning such as “Toilet #1: less than 15 in from side wall” or “Vanity #2: front clearance under 21 in”.

4. Estimating open floor area

The calculator estimates open floor area by subtracting the footprint of fixtures from the room area:

\[ A_\text{room} = L \times W \]

\[ A_\text{fixtures} = \sum_i (w_i \times d_i) \]

\[ A_\text{open} \approx A_\text{room} - A_\text{fixtures} \]

This is an approximation because it doesn’t account for overlapping fixtures or irregular shapes, but it’s useful for comparing different layouts.

Design tips for common bathroom layouts

Small 5' × 8' (1.5 × 2.4 m) bathroom

Place the tub or shower along the long wall.
Align toilet and vanity on the opposite wall to keep plumbing simple.
Keep the door swing from blocking the toilet or trapping someone behind it.

Primary bathroom with double vanity

Allow at least 36" (91 cm) clear in front of the vanity if two people will use it at once.
Consider a separate toilet compartment; allow a minimum of 30" × 60" (76 × 152 cm) inside.
Use this calculator to test different tub vs. shower sizes before committing.

Limitations and professional use

This bathroom layout calculator is ideal for homeowners, DIYers, and early‑stage design discussions. For permit drawings, accessibility design, or structural changes, always:

Verify all dimensions on site with a tape measure.
Check your local building code and plumbing code.
Consult a licensed architect, designer, or contractor when in doubt.