Planning guide
How Many Porta Potties Do I Need?
Count by guests and event length, adjust for alcohol, add accessible units and hand washing, or use the OSHA table for jobsites. The calculator does the math.
Porta potty calculator
Enter your guest or crew count below and the calculator gives the number of porta potties you need. It uses the same planning tables shown on this page, so the result matches each section. Tick alcohol, food or public event and it adds units, hand wash stations and ADA units to match.
standard units
Based on the tables on this page. Call to confirm your setup.
How many porta potties do I need for an event?
An event of up to 4 hours needs 1 standard porta potty per 50 guests. An event of 4 to 8 hours needs 1 per 35 guests. An all-day event needs 1 per 25 guests. So 100 guests for 4 hours need 2 units, and 100 guests for 6 hours need 3 units.
| Guests | Up to 4 hours | 4–8 hours | All day (8+ hours) |
|---|---|---|---|
| Up to 50 | 1 | 2 | 2 |
| 51–100 | 2 | 3 | 4 |
| 101–150 | 3 | 5 | 6 |
| 151–200 | 4 | 6 | 8 |
| 201–300 | 6 | 9 | 12 |
| 301–400 | 8 | 12 | 16 |
| 401–500 | 10 | 15 | 20 |
These planning ratios are our own, built from standard industry sizing charts and what keeps lines under about 5 minutes at peak times. They are a recommendation, not a law.
How many more porta potties if alcohol is served?
When alcohol is served, add 1 unit for every 3 units in the table, rounded up. A 150-guest wedding of 6 hours needs 5 units from the table. With a bar, add 2 more for a total of 7 units, or a 4-station restroom trailer plus 1 unit.
Worked example: the table says 5 units. 5 ÷ 3 = 1.67, rounded up to 2. Final count: 7 units.
How many accessible units do I need?
Public events need at least 5% of the porta potties in each cluster to be accessible, rounded up, with a minimum of 1. That is section 213.2 of the 2010 ADA Standards. A 12-unit cluster needs 1 ADA unit. A 30-unit cluster needs 2.
See the U.S. Access Board guide. The ADA unit counts toward your total. Private parties have no legal minimum, but one accessible unit helps older guests. More on the ADA unit page.
How many porta potties does a construction site need?
OSHA 29 CFR 1926.51(c) requires 1 toilet for 20 or fewer workers, 1 seat and 1 urinal per 40 workers above 20, and 1 seat and 1 urinal per 50 workers at 200 or more. We recommend 1 unit per 10 workers with weekly service so the tank lasts the full week.
| Workers | OSHA minimum | Recommended (weekly service) | Recommended (twice weekly) |
|---|---|---|---|
| 5 | 1 toilet | 1 | 1 |
| 15 | 1 toilet | 2 | 1 |
| 30 | 1 seat + 1 urinal | 3 | 2 |
| 60 | 2 seats + 2 urinals | 6 | 4 |
| 120 | 3 seats + 3 urinals | 12 | 8 |
Read the rule at osha.gov. Each standard unit has 1 seat and 1 urinal. Farms follow a different rule, OSHA 1928.110: 1 toilet and 1 hand washing facility per 20 field workers, within a quarter-mile walk.
How many hand wash stations do I need?
Plan 1 hand wash station for every 2 toilets at events with food, and 1 station per 20 workers on jobsites where crews eat on site. Events without food can rely on the sanitizer inside each unit. A 6-unit wedding with dinner, for example, needs 3 hand wash stations.
See hand wash station rental for sizes and placement.
More questions about this
How many porta potties for 100 guests?
100 guests need 2 standard units for up to 4 hours, 3 units for 4 to 8 hours, and 4 units for an all-day event. Add 1 more if alcohol is served.
How many porta potties for 200 guests?
200 guests need 4 units for up to 4 hours and 6 units for 4 to 8 hours. With a bar, plan on 8 units, or a 4-station restroom trailer plus 2 units.
How many porta potties for 50 guests?
50 guests need 1 standard unit for up to 4 hours and 2 units for a longer event.
When one unit says it serves 50, does that mean 50 people at once?
One unit serves about 50 guests over a 4-hour event, one person at a time. It does not mean 50 people at the same moment.
Do I need more units if most guests are women?
Women's visits take longer, so lines grow faster. If most guests are women, add 1 unit to the table count, or choose a restroom trailer with more stalls.
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