Calculates minimum water closets (toilets) and lavatories (sinks) for an office (Group D – business & personal services).
This minimum can be calculated either by office size (By Area) or by known headcount (By People).
1) Calculation basis
By Area assumes a default Group D fixture sizing factor of 14 m²/person (editable), and a 50/50 sex split.
By People uses your male/female headcount directly, this is recommended if you have actual headcount.
Enter the gross area served by the washroom fixtures.
Default 14 m²/person, Units are in m²/person
If either value is unknown, you can use the By Area method instead.
Advanced Settings
This is a rough planning tool (not a code-compliant layout). It is intended for early stage space planning only.
The calculator uses the dimensional modules below and adds a contingency.
Area is only shown when both male and female washrooms require ≥ 2 WCs.
Applied to base area.
Results update when you click Calculate.
Clears inputs and results.
Important: Codes can change and project conditions vary. Confirm with the latest Ontario Building Code and the Authority Having Jurisdiction (AHJ).
