How many porta potties do I need for my event?
One porta potty serves about 50 guests for a 4-hour event. Add 1 unit for every 2 hours past 4 hours, and add 1 unit (or 20%, whichever is more) when alcohol is served. A 200-guest, 4-hour event without alcohol needs 4 standard porta potties.
Porta potty calculator
Assumptions: 1 unit per 50 guests for 4 hours; +1 unit per extra 2 hours past 4; +1 unit (or +20%, whichever is more) with alcohol; 5% of units wheelchair-accessible (min. 1) for public events.
| Guests | 4 hours | 6 hours | 8 hours |
|---|---|---|---|
| 50 | 1 | 2 | 3 |
| 100 | 2 | 3 | 4 |
| 150 | 3 | 4 | 5 |
| 250 | 5 | 6 | 7 |
| 500 | 10 | 11 | 12 |
| 1,000 | 20 | 21 | 22 |
How do I adjust for alcohol, women and children?
Alcohol, crowds of mostly women, and children all raise restroom use. If the table says 4 units and beer is served, rent 5. If most guests are women, add 1 more unit or swap 1 standard unit for a restroom trailer stall. Family events with many small children benefit from 1 accessible unit for changing.
Worked example: a quinceañera with 220 guests from 7 p.m. to 1 a.m. (6 hours) with a bar.
- Base: 220 ÷ 50 = 4.4, round up to 5 units.
- Six hours instead of four: +1 = 6 units.
- Alcohol: +20% of 6 = 1.2, round up to 2 = 8 units.
A popular mix is 1 two-stall trailer plus 6 standard units.
How many porta potties do I need for a construction crew?
A construction crew needs 1 porta potty per 10 workers for a 40-hour week with weekly service. That is a service recommendation, not the law. OSHA 29 CFR 1926.51 sets the legal minimum at 1 toilet for 20 or fewer workers and 1 seat plus 1 urinal per 40 workers above that.
See the OSHA porta potty requirements guide for every crew size.
How many hand washing stations do I need?
Plan 1 hand washing station for every 2 to 4 porta potties at food events, and 1 per 20 workers for farm crews under OSHA 1928.110. Construction crews handling paints or chemicals need washing facilities under OSHA 1926.51(f).
Read the rules at OSHA 1926.51 and OSHA 1928.110.
How many porta potties do I need? questions
How many porta potties for 100 guests?
Two standard porta potties cover 100 guests for 4 hours. Make it 3 if alcohol is served or the event runs 6 hours.
How many porta potties for 300 people?
Six standard units cover 300 people for 4 hours. A bar or a 6-hour event pushes it to 7 or 8.
How many porta potties per person?
Plan 1 porta potty per 50 people for a 4-hour event, or 1 per 10 workers per week on a jobsite.
Is it better to rent one extra unit?
One spare unit costs less than a long line. For events over 200 guests, most hosts round up.
Does a restroom trailer replace porta potties?
A two-stall trailer handles about the same traffic as 2–3 standard units. Many hosts keep standard units near parking too.