Getting toilet cubicle requirements right is one of the most overlooked parts of commercial building design. Too few cubicles mean queues, complaints and possible code violations. Too many waste valuable floor space and budget. This guide walks you through how to calculate how many toilet cubicles your commercial building needs, step by step.
Why Toilet Cubicle Planning Matters
Washrooms are a basic requirement for occupancy approval. Authorities will not sign off a building that lacks the minimum number of sanitary facilities. Beyond compliance, good planning affects:
- Employee and visitor satisfaction: long queues and poorly maintained washrooms reflect badly on your business.
- Hygiene and health: adequate capacity reduces overcrowding and keeps facilities cleaner.
- Space efficiency: washrooms are non-revenue areas, so sizing them correctly protects usable floor area.
- Accessibility and inclusion: every building must serve people of all abilities.
Step 1: Identify the Building Type and Occupancy
Requirements vary widely by building use. An office, a shopping mall, a restaurant, a school and a hospital all have different needs. Start by classifying your building:
- Offices and business premises
- Retail and shopping centres
- Restaurants, cafés and entertainment venues
- Educational institutions
- Industrial and warehouse facilities
- Hospitals and healthcare buildings
- Hotels and hospitality spaces
Each category has its own ratio of people to fixtures, because usage patterns differ. A theatre sees a rush during the interval, while an office has steady use through the day.
Step 2: Estimate the Number of Occupants
Next, work out the maximum number of people who will use the building at one time. Use:
- Actual headcount for offices with fixed staff, plus visitors.
- Floor area per person where headcount is unknown. Building codes publish occupant load factors, for example a set number of square metres or square feet per person for each building type.
- Seating capacity for restaurants, auditoriums and cinemas.
Always plan for peak occupancy, not the daily average. Consider future growth too. If you expect to add staff in the next few years, build in some capacity now.
Step 3: Split Occupants by Gender
Most codes require separate facilities for men and women once occupancy passes a set threshold. If you have no data, assume a 50/50 split. If your workforce or visitor profile is clearly skewed, adjust accordingly. Many designers also provide more cubicles for women because women typically spend longer per visit and men’s facilities can use urinals.
Also check whether local rules require or encourage gender-neutral or single-occupancy cubicles, which are increasingly popular in modern offices.
Step 4: Apply the Code Ratio for Your Building Type
This is the core of the calculation. Building codes set the minimum number of water closets (WCs), urinals and washbasins per number of occupants. Which code applies depends on where you build. Common references include:
- International Plumbing Code (IPC) in the USA
- BS 6465-1 in the UK
- National Building Code (NBC) in India
- Local municipal or state building regulations, which often add their own rules
The table below shows an example of an office (business occupancy) ratio in the style of the IPC. It is for illustration only, so always confirm the current figures in your local code.
| Fixture | Ratio (business occupancy) |
| Water closets | 1 per 25 occupants for the first 50, then 1 per 50 for the remainder |
| Washbasins | 1 per 40 occupants for the first 80, then 1 per 80 for the remainder |
Step 5: Worked Example
Let’s say you are designing a 200-person office with an even gender split (100 men, 100 women).
Water closets for women:
- First 50 people ÷ 25 = 2
- Remaining 50 people ÷ 50 = 1
- Total: 3 WCs
Water closets for men:
- The same ratio gives 3 fixtures, and urinals can substitute for some of them where your code allows.
Washbasins per gender:
- First 80 people ÷ 40 = 2
- Remaining 20 people ÷ 80 = 0.25, rounded up to 1
- Total: 3 washbasins each
So this office needs about 6 toilet cubicles or fixtures in total, plus 6 washbasins, before adding accessible provision. Always round up, never down.
Step 6: Add Accessible Toilet Cubicles
Accessibility is a legal requirement in most countries. Under standards such as the ADA in the USA, the Equality Act and Approved Document M in the UK, and India’s Harmonised Guidelines, you typically need:
- At least one accessible cubicle per washroom block, or a separate unisex accessible toilet
- Wider door openings and a larger turning space for wheelchair users
- Grab rails, a suitable seat height and an emergency alarm
- Step-free access to the washroom
Accessible cubicles are noticeably larger than standard ones, so include them early in your floor plan rather than adding them as an afterthought.
Step 7: Plan Cubicle Size and Layout
Once you know the number of cubicles, plan the space. As a rough guide:
- Standard cubicle: around 800–900 mm wide and 1,500 mm deep
- Accessible cubicle: considerably larger, often around 1,500 mm × 2,000 mm or more, depending on local standards
- Circulation space: enough clearance in front of cubicle doors for doors to open and people to pass
Also consider:
- Door swing direction (outward-opening doors save space, but check privacy and code rules)
- Privacy through floor-to-ceiling partitions or gap-free designs
- Ventilation and natural light
- Plumbing access through shared service ducts to cut installation costs
- Placement near stairs, lifts and main circulation routes, but not opening directly onto reception or dining areas
Step 8: Choose Durable Cubicle Materials
Commercial washrooms see heavy use, so material choice affects long-term cost. Common options include:
- High-pressure laminate (HPL): affordable, wide range of finishes
- Solid grade laminate (SGL): strong, moisture-resistant and vandal-resistant
- Powder-coated metal: durable and easy to clean
- Stainless steel: hygienic and ideal for high-traffic or industrial sites
- Compact laminate: waterproof and long-lasting, popular for wet areas
For areas with high humidity or heavy traffic, such as malls, airports, gyms and schools, prioritise moisture-resistant, easy-to-clean materials.
Common Mistakes to Avoid
- Planning for average rather than peak occupancy
- Forgetting visitors and customers in headcount
- Ignoring accessibility until late in the design
- Not checking local codes, which vary by region and may be stricter than national ones
- Under-sizing circulation space so cubicles feel cramped
- Choosing cheap materials that need early replacement
Quick Checklist
- Confirm building type and applicable code
- Calculate peak occupancy
- Split by gender and apply code ratios
- Round up all fixture counts
- Add accessible provision
- Plan sizes, layout and ventilation
- Select durable, low-maintenance materials
- Get design approval from the local authority
Frequently Asked Questions
How many toilets does a commercial building need?
It depends on building type and occupancy. For offices, codes commonly require roughly one WC per 25 people for the first 50, then fewer per additional occupant. Always check your local code.
Do I need separate toilets for men and women?
Most codes require separate facilities above a set occupancy, but single-occupancy unisex cubicles are accepted in many places, especially in smaller buildings.
How much space does a toilet cubicle need?
A standard cubicle is generally about 800–900 mm wide and 1,500 mm deep. Accessible cubicles need much more space.
Should I plan for future growth?
Yes. Adding cubicles later is far more costly than planning capacity now.
About Restloo
Getting toilet cubicle requirements right is easier with a supplier that understands commercial washrooms. Restloo provides toilet cubicles designed for durability, hygiene and clean design, suited to offices, malls, schools, hospitals and other commercial spaces. Whether you need help estimating cubicle numbers, choosing materials or planning a layout, the Restloo team can support you from design to delivery. Visit restloo.com to explore our range or request a quote for your project.