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IBC 2024Table 2902.1Selected uses only

IBC 2024 Plumbing Fixture
Count Calculator

Calculate the table minimum for fifteen implemented use descriptions. This bounded tool applies the default equal division between sexes, stepped ratios where required, and upward rounding.

Who it's for: architects and code consultants sizing plumbing fixture counts at construction documents or permit review, once occupant load and use are established.

Selected Table 2902.1 rowsNo urinal substitution or mixed-use aggregation
Calculate a selected use

Prefilled inputs illustrate the 200-person Business example below. Edit them for your task; no result is calculated automatically.

How to use this calculator

1
Determine occupant load separately
Use the actual function of the space and adopted code. This calculator does not determine occupant load.
2
Select the exact supported use
Only fifteen use descriptions are implemented; a broad occupancy label is not a substitute for the table description.
3
Apply the default distribution
The total is divided equally under §2902.1.1. For an odd total, each mathematical half retains the 0.5 person.
4
Calculate and round
Water closets and lavatories are calculated for each sex. The Business row uses its stepped ratios; each final fractional count rounds upward.
5
Complete excluded checks
Verify facility configuration, approved distributions, multiple occupancies, substitutions, exceptions, accessibility, IPC provisions, and amendments separately.

The formula

Constant ratio: fixtures = ceiling(applicable population ÷ persons per fixture). For the Business stepped ratios, calculate the first band and remainder, add the fractional requirements, then round the sum upward. Drinking fountains use total occupant load.

Worked example

Example
For a Business occupant load of 200, each default half is 100. Each half requires ceiling(50/25 + 50/50) = 3 water closets and ceiling(80/40 + 20/80) = 3 lavatories. The total also produces 2 drinking fountains and 1 service sink.

When this estimate will be off

  • Implements fifteen occupant-load-based Table 2902.1 descriptions: nine Assembly descriptions (theaters; nightclubs and bars; restaurants; casino gaming; auditoriums, galleries and museums; passenger terminals; places of worship; indoor arenas; outdoor stadiums), general Business, ambulatory care, Educational, Factory/Industrial, Mercantile, and low/moderate-hazard Storage.
  • Uses the §2902.1.1 default equal distribution; it does not approve statistical distributions, all-gender configurations, or single-user allocation.
  • Does not calculate urinals or substitutions; the table directs urinal provisions to the International Plumbing Code.
  • Does not aggregate multiple occupancies, and does not calculate Institutional rows (counted by care recipients, sleeping units or cells), Residential rows (counted by dwelling or sleeping units), bathtubs and showers, swimming-pool fixtures (International Swimming Pool and Spa Code §609), accessibility, or amendments.
  • For the marked Assembly descriptions, include seasonal outdoor seating and entertainment areas in the occupant load (Table 2902.1 note d). Ambulatory care asks for one service sink per floor; this tool shows one.
  • The result is a model-code table calculation, not permit approval or a complete plumbing design.

Frequently asked questions

A common mistake: choosing a broad occupancy label instead of the exact Table 2902.1 description, or leaving seasonal outdoor seating out of the occupant load for the Assembly descriptions that count it.

No. Occupant load is a prerequisite determined from the actual function of each space under the adopted code.

The former calculator collapsed materially different descriptions. This release implements the Assembly, Business, Educational, Factory, Mercantile and Storage rows that are based on occupant load; rows counted in dwelling units, sleeping units or care recipients need other inputs and are not offered.

The default calculation divides the total equally. An occupant load of 101 therefore uses 50.5 for each half before applying and rounding the fixture ratios.

No. The IBC table directs urinal provisions to the IPC; no automatic water-closet substitution is assumed.

Table 2902.1 sets Business lavatories at 1 per 40 people for the first 80, then 1 per 80 for the remainder. Business water closets are 1 per 25 for the first 50, then 1 per 50 for the remainder — applied separately to each half of the occupant load.

Table 2902.1 sets Mercantile at 1 water closet per 500 people, 1 lavatory per 750, and 1 drinking fountain per 1,000 — much lower fixture density than Business because retail floor area holds far more people per fixture-worthy visit.

Sources

  • ICC — 2024 IBC Chapter 29 — §2902.1, Table 2902.1 (Assembly no. 1 rows, Business including ambulatory care, Educational, Factory, Mercantile, Storage rows), §2902.1.1, table notes, §2902.2, and §2902.6
  • ICC — 2024 IPC Chapter 4 — Required separately for urinals, drinking-fountain details, installation, and other plumbing provisions

Sources and review record

Sources and method basis

  • IBC 2024 §2902.1, Table 2902.1, §2902.1.1, table notes, §2902.2, and §2902.6
  • IPC 2024 Chapter 4 for excluded urinal, drinking-fountain, fixture, and installation provisions
  • https://codes.iccsafe.org/

Limitations

  • Implements fifteen selected use descriptions with the default equal distribution only; mixed occupancies, other table rows, urinals, facility configuration, accessibility, IPC provisions, adoption, and amendments are excluded.

This free IBC 2024 Plumbing Fixture Calculator is built and maintained by DataDrivenAEC, using the relevant codes and standards. It does not substitute for professional judgment.