How Many Porta Potties Do I Need?
Here is how many porta potties you need, worked out the way our dispatch team does it. Enter your guests and hours in the calculator, or read the chart, then adjust for alcohol, food and accessibility.
A real Nashville dispatcher answers 7 days a week, 7:00 AM – 7:00 PM.
- Delivery area
This sizing method works for every event and job site we serve across Nashville and Middle Tennessee.
- Arrival
Once you have your count, call by noon for same-day or book by 5 PM for next-day delivery.
- Which unit
One standard unit covers about 50 guests for 4 hours, or up to 10 workers for a week with weekly service.
- Cleaning
Multi-day events can add a mid-event service visit instead of extra units. Just ask when you call.
- Full cost
Your itemized quote prices the exact unit count, delivery and pickup, any extras and tax, so you can plan ahead.
How do you calculate how many porta potties you need?
Multiply guests by event hours and divide by 200, then round up. One standard porta potty handles about 200 guest-hours, which is 50 guests for 4 hours. A 120-guest, 5-hour party needs 3 units (120 × 5 ÷ 200 = 3). Then add units for alcohol and stations for food.
Porta potty calculator
Assumptions: 1 standard unit ≈ 200 guest-hours; alcohol adds 1 unit per 4 (minimum 1); accessible units = 5% of units, minimum 1 (2010 ADA Standards §213.2); food adds 1 station per 2 units (our recommendation). Confirm legal minimums with your venue or permit office.
How many porta potties do you need per guest and hour?
The chart below uses the 200 guest-hour method with no alcohol. A 4-hour event needs 1 standard unit per 50 guests. A 6-hour event needs 1 per about 33 guests. An 8-hour event needs 1 per 25 guests. Round up any fraction to the next whole unit.
| Guests | Up to 2 hrs | 4 hrs | 6 hrs | 8 hrs |
|---|---|---|---|---|
| 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 |
| 1,000 | 10 | 20 | 30 | 40 |
How many extra porta potties do you need when alcohol is served?
Add 1 porta potty for every 4 units on the chart when alcohol is served, rounding up, with a minimum of 1 extra unit. If the chart says 5 units, add 2, for 7. If the chart says 3 units, add 1, for 4. Drinks raise how often guests use the restroom.
Worked example: A 150-guest wedding reception runs 6 hours with a bar. 150 × 6 ÷ 200 = 4.5, which rounds up to 5 units. Alcohol adds 1 per 4 units: 5 ÷ 4 = 1.25, rounded up to 2. Total: 7 units, and at least 1 should be wheelchair-accessible. See wedding restroom options for flushing units and trailers.
How many wheelchair-accessible porta potties are required?
The 2010 ADA Standards, section 213.2, call for at least 5% of portable toilet units in each cluster to be accessible, with a minimum of 1. A cluster of 1 to 20 units needs 1 accessible unit. A cluster of 21 to 40 units needs 2. Confirm your event's requirements with your venue or permit office.
Read the official text in the 2010 ADA Standards for Accessible Design. Our wheelchair-accessible units page covers placement and turning space.
How many porta potties does a construction site need?
OSHA 29 CFR 1926.51(c) Table D-1 sets the legal minimum: 1 toilet for 20 or fewer workers, then 1 toilet seat and 1 urinal per 40 workers, and 1 seat and 1 urinal per 50 workers at 200 or more. Our recommendation for 40-hour weeks with weekly service is 1 standard unit per 10 workers.
| Workers | OSHA Table D-1 minimum | Our recommendation (weekly service) |
|---|---|---|
| 1–10 | 1 toilet | 1 unit |
| 11–20 | 1 toilet | 2 units |
| 21–40 | 1 seat + 1 urinal | 3–4 units |
| 41–80 | 2 seats + 2 urinals | 5–8 units |
| 200+ | 1 seat + 1 urinal per 50 | 1 unit per 10, or add service days |
Legal minimum: OSHA 1926.51 Table D-1 above, plus handwashing under 1926.51(f). Tennessee runs a state plan (TOSHA) that follows these construction standards.
Our recommendation: 1 standard unit per 10 workers for a full work week. Above 10 workers per unit, add a second weekly service. This is not legal advice.
More detail for builders is in our OSHA porta potty requirements guide and on the construction site toilets page.
When do you need hand washing stations, and how many?
Add 1 hand washing station for every 2 porta potties at any event that serves food, rounding up. That is our recommendation, not a legal rule. A 6-unit food festival gets 3 stations. Job sites must provide washing facilities under OSHA 1926.51(f), which a station or sink unit can cover.
Compare stations and sink-inside units on the hand washing station rental page.
Porta potty count questions
How many porta potties do I need for 100 guests?
100 guests for 4 hours need 2 standard units (100 × 4 ÷ 200 = 2). For 6 hours, 3 units. With alcohol, add 1 more. At least 1 of the units should be wheelchair-accessible for a public event.
How many porta potties for 200 people at an all-day event?
200 people for 8 hours need 8 standard units (200 × 8 ÷ 200 = 8). Add 2 if alcohol is served, for 10. Ask about a mid-event service visit for events longer than 8 hours.
Do more women at an event change the count?
Women use restrooms longer on average, so lines form faster at events with mostly women guests, like bridal showers. Round up rather than down, and consider 1 extra unit when the guest list is mostly women.
Does a restroom trailer replace several porta potties?
For planning, we count each trailer station like one standard unit. A 2-station trailer covers about 100 guests for 4 hours. Large weddings often pair a trailer with 1 or 2 standard units.
How many porta potties does a small job crew need?
OSHA requires at least 1 toilet for 20 or fewer workers. Our recommendation is 1 standard unit per 10 workers with weekly service, so a 5-person crew needs 1 unit and a 15-person crew needs 2.
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(615) 237-60887 days a week, 7:00 AM – 7:00 PM- Itemized quote: unit, delivery & pickup, any rush fee, service and tax
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