A headcount starts the estimate; it does not finish it.
Choose with the use in mind
For a worksite, share the largest shift, overlap between trades and the hours worked. For an event, explain peak attendance, event length, food or beverage service and the program schedule. Distinguish people present at once from a total that turns over throughout the day.
Make the location work
List permanent bathrooms only if they will be open, reachable and suitable for the intended users. Discuss accessible facilities and handwashing separately. The service schedule can affect the arrangement, but additional toilets are not a substitute for an appropriate cleaning plan.
Confirm the full arrangement
Ask for a recommendation based on the complete brief and applicable requirements. There is no universal guest-to-toilet number that fits every occasion. If attendance or crew size is uncertain, give a realistic range and agree when the plan should be reviewed.
Leave room for changes
If your dates, site access or expected use change, discuss the arrangement before the next delivery or service visit. Keep the agreed contact details available to the person managing the site.
Delivery and pickup checklist