How Many Porta Potties Do I Need? Calculator & Chart
Work out how many porta potties you need for a party, wedding or jobsite in under a minute, using the industry chart and OSHA rules.
A real person answers live Mon–Sat 7:00 am – 7:00 pm. Quotes back in under 1 business hour.
- Base rule
- Plan 1 standard unit per 50 guests for a 4-hour event, rounding up. That means 2 units for 100 guests.
- Long events
- Running past 4 hours? Add 1 unit per 100 guests for every extra 2 hours of event time.
- Alcohol
- Serving beer or wine? Add 1 unit per 100 guests, with a minimum of 1 extra unit on site.
- Construction
- OSHA requires 1 toilet for up to 20 workers. We suggest 1 unit per 10 workers with weekly service.
- Accessible
- Public events need at least 5% wheelchair-accessible units, minimum 1. Add hand-wash stations when food is served.
Porta potty calculator for events
Enter your guest count, event length, and whether you're serving food and alcohol. The calculator applies the standard rule of about 1 porta potty per 50 guests for 4 hours, then adds units for extra hours and alcohol. It also tells you how many accessible units and hand-wash stations to add.
Method: about 1 standard unit per 50 guests for 4 hours, +1 unit per 100 guests for each extra 2 hours, +1 per 100 guests when alcohol is served, 5% accessible (2010 ADA Standards §213.2). Ask us for crowds over 1,000.
Porta potty chart by guest count
For a 4-hour event, 100 guests need 2 porta potties, 200 guests need 4, and 300 guests need 6. Serving alcohol adds 1 unit per 100 guests. A 6-hour event with alcohol adds another 1 per 100. These counts assume standard units serviced before the event, not during it.
| Guests | 4 hours, no alcohol | 4 hours, with alcohol | 6 hours, with alcohol |
|---|---|---|---|
| 50 | 1 | 2 | 3 |
| 100 | 2 | 3 | 4 |
| 150 | 3 | 5 | 7 |
| 200 | 4 | 6 | 8 |
| 250 | 5 | 8 | 11 |
| 300 | 6 | 9 | 12 |
| 500 | 10 | 15 | 20 |
Worked example: 150-guest wedding, 6 hours, open bar
A 150-guest wedding lasting 6 hours with an open bar needs 7 standard porta potties, or a 2-stall restroom trailer plus 3 standard units. The math is 3 base units, plus 2 for the extra 2 hours, plus 2 for alcohol. At least 1 should be wheelchair-accessible.
- 150 guests ÷ 50 = 3 base units.
- 6 hours is 2 hours over 4, so add 1 unit per 100 guests: 150 → +2 units.
- Alcohol served: 1 per 100 guests: 150 → +2 units.
- Total: 7 units. Make 1 accessible (5% of 7, rounded up).
- Food served: add 3 hand-wash stations (1 per 2–3 toilets).
Weddings often swap several units for a restroom trailer. See wedding restroom options.
How many porta potties does a construction site need?
OSHA 29 CFR 1926.51(c) Table D-1 requires 1 toilet for 20 or fewer workers, 1 toilet seat and 1 urinal per 40 workers above 20, and 1 seat and 1 urinal per 50 workers above 200. That is the legal minimum. We recommend 1 standard unit per 10 workers with weekly service.
| Workers | OSHA minimum (Table D-1) | Our recommendation, weekly service |
|---|---|---|
| 1–10 | 1 toilet | 1 standard unit |
| 11–20 | 1 toilet | 2 units |
| 21–40 | 1 seat + 1 urinal per 40 | 3–4 units |
| 60 | 2 seats + 2 urinals | 6 units, or 4 with twice-weekly service |
| 220 | 5 seats + 5 urinals | Call for a site plan |
Read the official text at OSHA 1926.51. Confirm site-specific rules with your GC or inspector; this isn't legal advice. More on jobsite porta potty rentals and the OSHA rules for Ohio job sites.
How many accessible units and hand-wash stations?
The 2010 ADA Standards section 213.2 call for at least 5% of portable toilets in each cluster to be accessible, with a minimum of 1. Add 1 hand-washing station for every 2 to 3 toilets when food is served, and at least 1 per cluster at any event with kids.
Official source: 2010 ADA Standards for Accessible Design. See our wheelchair-accessible unit and hand-washing stations.
Porta potty count questions
Is one porta potty enough if it's the only bathroom at my party?
One standard porta potty handles about 50 guests for a 4-hour party. For more guests, a longer party, or beer and wine, add units using the calculator above. If guests can also use a bathroom in the house, you can usually drop 1 unit.
How many porta potties do I need for 150 people?
A 4-hour event with 150 guests needs 3 standard porta potties. Serving alcohol adds 2 more, for 5. A 6-hour event with alcohol needs 7. Make at least 1 of them wheelchair-accessible.
How many porta potties does a construction crew of 25 need?
OSHA Table D-1 requires at least 1 toilet seat and 1 urinal for 25 workers. Our recommendation is 3 standard units with weekly service, which works out to about 1 unit per 10 workers.
Do I need an accessible porta potty at a private party?
Private backyard parties aren't covered by the ADA rule for public events, but an accessible unit is still the right call if any guest uses a wheelchair or walker. Public events need at least 5% accessible units, minimum 1.
How many hand-washing stations do I need?
Plan 1 hand-washing station for every 2 to 3 toilets when food is served. One 2-basin station handles roughly 200 to 250 washes before it needs a refill.
Will a flushing unit work for 150 guests?
One flushing unit holds about 250–300 flushes, so it works for a few dozen guests over an evening. For 150 guests, use 3 or more flushing units, or a restroom trailer.
Send us your headcount, get your count
Give us the guest or crew count and dates. We'll confirm the number of units and send one itemized price.
(216) 223-2644Tap to call. Live answer Mon–Sat 7:00 am – 7:00 pm. Same-day cutoff is 12:00 noon.