How Many Porta Potties Do I Need?
Enter your guest count or crew size. The calculator uses the same planning method we use on the phone, with every step shown below.
Phones answered Mon–Sat, 7 a.m.–7 p.m. Most callers get an itemized price on the first call.
How many porta potties for 100 guests?
A 100-guest event lasting 4 hours needs 2 standard porta potties. A 100-guest, 5-hour wedding with a bar needs 4: 2 for the guests, 1 more for the hour past 4, and 1 more because alcohol is served. Add 1 handwashing station for every 4 toilets.
| Guests | 4 hours | 8 hours | 4 hours, with alcohol | 8 hours, with alcohol |
|---|---|---|---|---|
| 25 guests | 1 | 2 | 2 | 3 |
| 50 guests | 1 | 2 | 2 | 3 |
| 100 guests | 2 | 3 | 3 | 4 |
| 150 guests | 3 | 5 | 4 | 7 |
| 200 guests | 4 | 6 | 5 | 8 |
| 300 guests | 6 | 9 | 8 | 12 |
| 500 guests | 10 | 15 | 13 | 19 |
Kingston planning method (see the steps below). It is our recommendation, not a legal minimum.
How does the porta potty calculation work?
The calculation starts with 1 standard porta potty for every 50 guests at an event up to 4 hours. Each extra 4 hours adds 1 unit per 100 guests, alcohol adds 1 unit for every 4 already counted, and the total always rounds up to a whole unit. Handwashing is 1 station per 4 toilets.
Base count
Guests divided by 50, rounded up. 120 guests = 3 units.
Long events
For each 4 hours past the first 4, add guests divided by 100, rounded up. 120 guests for 8 hours = 3 + 2 = 5 units.
Alcohol
Add 1 unit for every 4 already counted, rounded up. 5 units with a bar = 5 + 2 = 7 units.
Accessibility
Make at least 5 percent of each cluster wheelchair-accessible, and never fewer than 1 (2010 ADA Standards §213.2).
Handwashing
1 station per 4 toilets, plus 1 at each food area.
How many porta potties does a construction site need?
A construction site with 20 or fewer workers needs 1 toilet under OSHA 29 CFR 1926.51 Table D-1. Sites with 20 to 199 workers need 1 toilet seat and 1 urinal per 40 workers, and sites with 200 or more need 1 seat and 1 urinal per 50 workers. Each standard unit has a seat and a urinal.
| Workers | Minimum units |
|---|---|
| 10 | 1 |
| 20 | 1 |
| 30 | 1 |
| 45 | 2 |
| 80 | 2 |
| 120 | 3 |
| 200 | 4 |
| 300 | 6 |
Source: OSHA 29 CFR 1926.51. Farms with 11 or more field workers follow 29 CFR 1928.110: 1 toilet and 1 handwashing facility per 20 workers, within a quarter-mile walk.
Do permitted public events need more units?
Permitted public events can carry a legal minimum above our planning count. The City of St. Louis sets 10 toilets and 2 handwashing stations per 1,000 attendees for events over 8 hours with alcohol, and 6 toilets and 2 stations without alcohol, with toilets serviced at least every 24 hours.
Source: City of St. Louis special event requirements. Other cities set their own rules; check your permit. This is general guidance, not legal advice.
Sizing questions
How many porta potties for 50 people?
One standard porta potty covers 50 guests for up to 4 hours. For 5 to 8 hours, or with a bar, plan 2.
How many porta potties for 200 guests?
A 4-hour event for 200 guests needs 4 units. An 8-hour event with alcohol needs 8 by our method, plus 2 handwashing stations.
Do women need more units?
Lines form faster when most guests are women. Add 1 unit for every 4 if the crowd is mostly women, such as a bridal shower.
How many uses does one porta potty hold?
A standard unit holds roughly 200 uses before it needs pumping. That is why long events and crews need a service schedule, not just more units.
Is one restroom trailer enough for 150 guests?
One 2-stall trailer handles about 100 to 130 guests at a 5-hour reception. For 150, add a deluxe unit beside it for the after-dinner peak.
Send us your count for a quote
Calling (636) 200-9910 is the fastest way to a price and a delivery time. Prefer writing? Send the six details below and we reply with a full itemized price, usually within one business hour during Mon–Sat, 7 a.m.–7 p.m., so you can share it with whoever signs off.
- One price covering the unit, delivery, pickup and any servicing
- No fuel surcharge added after the quote
- Free changes or cancellation up to 24 hours before delivery