Sizing guide · Reviewed October 2026
How Many Porta Potties Do I Need?
Plan 1 standard porta potty for every 50 guests over a 4-hour event, or 1 unit per 10 workers on a 40-hour job week with weekly service. Enter your numbers below and the calculator shows every step of the math.
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How many porta potties do I need for my event?
An event needs 1 standard porta potty per 200 guest-hours, which is 50 guests for 4 hours. Multiply guests by hours, divide by 200, and round up. A 120-guest, 6-hour party needs 120 × 6 ÷ 200 = 3.6, rounded up to 4 units.
| Guests | 2 hrs | 4 hrs | 6 hrs | 8 hrs |
|---|---|---|---|---|
| 25 | 1 | 1 | 1 | 1 |
| 50 | 1 | 1 | 2 | 2 |
| 100 | 1 | 2 | 3 | 4 |
| 150 | 2 | 3 | 5 | 6 |
| 200 | 2 | 4 | 6 | 8 |
| 300 | 3 | 6 | 9 | 12 |
| 500 | 5 | 10 | 15 | 20 |
Adjusting the count
- Alcohol served: add 1 unit for every 4. If the table says 4, add 1 for 5 total.
- Public event: make at least 5% of each cluster, minimum 1, wheelchair-accessible (2010 ADA Standards §213.2).
- Food served: add 1 hand-wash station per 3 toilets; otherwise 1 per 5.
- Mostly women and kids: round up one more unit; seat-only use takes longer.
The 200 guest-hour figure is Cory Rental Works' dispatch planning method, based on a standard unit's roughly 200-use tank. Worked example: a 150-guest, 5-hour wedding with a bar: 150 × 5 ÷ 200 = 3.75 → 4 units, plus 1 for alcohol = 5 units.
How many porta potties does a construction site need?
A construction site needs at least 1 toilet for 20 or fewer workers under OSHA 29 CFR 1926.51 Table D-1. For a 40-hour week with one weekly service visit, plan 1 standard unit per 10 workers so the tank does not fill before the driver returns.
| Workers | OSHA minimum | Weekly service | Twice-weekly service |
|---|---|---|---|
| 1–10 | 1 | 1 | 1 |
| 11–20 | 1 | 2 | 1 |
| 21–40 | 1 seat + 1 urinal | 3–4 | 2 |
| 41–80 | 2 seats + 2 urinals | 5–8 | 3–4 |
| 81–120 | 3 seats + 3 urinals | 9–12 | 5–6 |
Full rule text and farm rules are on the OSHA porta potty requirements guide. Ready to book? See construction rentals or event rentals.
Porta potty sizing questions
How many porta potties do I need for 100 guests?
100 guests at a 4-hour event need 2 standard porta potties. If the event runs 8 hours, plan 4. If alcohol is served at a 4-hour event, plan 3.
How many porta potties for 50 people?
50 people at a 4-hour event need 1 standard porta potty. Add a second unit if the event runs past 4 hours, alcohol is served, or most guests are women and kids.
How many porta potties for 200 guests?
200 guests at a 4-hour event need 4 standard porta potties, or 5 if alcohol is served. Make 1 of them wheelchair-accessible if the public attends.
Does alcohol really change the count?
Guests drinking beer or wine use restrooms more often. Our method adds 1 unit for every 4 units when alcohol is served, rounded up.
How many porta potties for 30 workers?
OSHA requires at least 1 seat and 1 urinal for 30 workers, which is 1 standard unit. With weekly service we recommend 3 units, or 2 units with twice-weekly service.
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