How many do you
actually need?
Events scale by guest count and duration. Construction scales by crew size. These are two different standards and mixing them up is the most common ordering mistake there is. Pick a mode and move the sliders.
Total restrooms 3. Reasonable planning band 2–4 depending on layout and how hard the peak hits.
Single day event. No servicing needed. Delivery the day before, pickup the next business day.
- ›Base requirement for 150 guests over 5 hours: 3 units.
- ›Alcohol service adds 20 percent. Published guidance ranges from 15 to 30 percent, so treat this as the middle of that band.
- ›Accessibility: at least 5 percent of units accessible with a minimum of one, so 1 of the 3 should be ADA units.
- ›Handwashing at one station per four toilets.
Planning estimate from published industry tables. Suppliers will confirm against your site.
How this is calculated
How does this calculator work?
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Event mode interpolates the published portable sanitation capacity tables across guest count and event duration, then applies adjustments for alcohol service, the five percent accessibility standard and handwashing ratios. Construction mode uses the one-unit-per-ten-workers standard with weekly service.
Why is it a table and not a formula?
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Because demand saturates in both directions. Doubling event length does not double units, since the same guests cycle through, and units required per guest falls as crowds get large. The industry publishes a two dimensional table for exactly that reason, and we interpolate between the published anchors rather than inventing a curve.
Is this an official requirement?
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No. It is a planning estimate based on published industry guidance. Local permit requirements, venue rules and health department expectations can differ. Suppliers will confirm the count against your actual site.
Why does alcohol add units?
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Consumption goes up meaningfully with bar service. Published guidance puts the adjustment at fifteen to thirty percent. We apply twenty percent as the middle of that band. An open bar running several hours sits at the top of the range.