Toilet calculator

Use the toilet calculator to help work out how many toilet pans, basins and urinals to include in buildings.

The calculator:

  • is designed to be used in conjunction with Acceptable Solution G1/AS1
  • uses the method contained in G1/AS1 for determining the number of required toilet pans, urinals and basins for use in buildings 
  • is intended for use by designers and building consent authorities
  • does not change the requirements that have been in place since 2000
  • is guidance under section 175 of the Building Act 2004.

The calculator works out the number of toilet pans, basins and urinals from either:

  1. the building use and the number of people using the building, if known, or
  2. the building use and floor areas which are used to calculate the occupant density.

Limitations of the calculator

The calculator, on its own, will not produce a Building Code compliant solution as it does not cover:

  • allocation and distribution of accessible toilet facilities
  • definition of, or the distribution of unisex toilet facilities
  • space requirements for toilets or accessible layouts
  • the 'floor area' options are extensive and allow for a number of different building configurations
  • calculation of showers.

The user should note the ‘occupant density’ menu option list is extensive and allows for a number of different building uses. Not all of the options will be relevant to the selected building use.

Each option provided by the toilet calculator shows the minimum number of accessible facilities required. Each accessible facility includes an accessible toilet pan and a basin.

The number of accessible toilet facilities shown is in addition to the number of male/female/unisex toilet facilities shown:

e.g. 5 male toilet pans + 5 female toilet pans + 2 accessible toilet pans = 12 toilet pans in total.


Access the toilet calculator by mobile phone

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This information is published by the Ministry of Business, Innovation and Employment’s Chief Executive. It is a general guide only and, if used, does not relieve any person of the obligation to consider any matter to which the information relates according to the circumstances of the particular case. Expert advice may be required in specific circumstances. Where this information relates to assisting people: