How Many Porta Potties Do I Need?
Enter your guests and hours, or your crew size, to get a unit count, the ADA share and a rough budget.
Event planning table
Standard units, using about 1 unit per 50 guests for 4 hours and more for longer events.
| Guests | Hours | No alcohol | With alcohol |
|---|---|---|---|
| 50 | 4 | 1 | 2 |
| 100 | 4 | 2 | 3 |
| 150 | 5 | 4 | 5 |
| 200 | 6 | 6 | 7 |
| 300 | 6 | 8 | 10 |
| 500 | 8 | 16 | 20 |
| 1000 | 8 | 32 | 40 |
Construction sites: the OSHA minimum
| Number of employees | Minimum facilities |
|---|---|
| 20 or fewer | 1 |
| 20 or more | 1 toilet seat and 1 urinal per 40 workers |
| 200 or more | 1 toilet seat and 1 urinal per 50 workers |
Source: OSHA 29 CFR 1926.51, Table D-1.
Photo: WWB, CC BY-SA 4.0, via Wikimedia Commons. All photo credits
How the calculator works
- Events: about 1 unit per 50 guests for a 4-hour event (a rule of thumb ZTERS also publishes), plus 15% for each extra hour and 25% more with alcohol.
- ADA: §213.2 Exception 3 requires “no more than 5 percent” of each cluster to be accessible; in practice, plan at least one accessible unit per cluster when the event is open to the public (2010 ADA Standards).
- Handwashing: about one station per 10 units. OSHA requires washing facilities on construction sites.
- Budget: $150–$300 per standard unit per event, or $125–$275 per unit per four-week site cycle (published 2026 national ranges).
Results are planning estimates, not a quote. Your provider will adjust for crowd mix, layout and service schedule. Compare rental prices next.
Frequently asked questions
How many porta potties do I need for 100 guests?
About 2 for a 4-hour event, or 3 if alcohol is served. Make one of them ADA accessible if the event is open to the public.
How many porta potties do I need for 200 guests?
About 6 for a 6-hour event, or 7 with alcohol.
How many porta potties does OSHA require per worker?
1 toilet for 20 or fewer workers; 1 toilet seat and 1 urinal per 40 workers from 20 workers; 1 toilet seat and 1 urinal per 50 workers from 200 (29 CFR 1926.51 Table D-1).
How many ADA porta potties do I need?
Under §213.2 Exception 3 of the 2010 ADA Standards, no more than 5 percent of the portable toilets in each cluster are required to be accessible. The practical reading is at least one accessible unit per cluster for events open to the public. Construction-only units are exempt (§203.2).