How Many Porta Potties Do I Need?
How many porta potties you need depends on head count, hours and whether alcohol or food is served. Enter your numbers below for a starting count, then read the method and worked examples. Job sites follow the OSHA table instead.
Quote requests get a call back within 30 minutes during business hours.
How many porta potties do I need for my event? Try the calculator
The porta potty calculator below uses our planning method: 1 standard unit per 50 guests for up to 4 hours, 1 per 40 guests for 5 to 8 hours, and 1 per 30 guests beyond 8 hours. Alcohol adds 1 unit for every 4 in the base count. The result includes the accessible unit count.
Assumptions in the calculator
- Standard units rated for about 200 uses between services.
- Guests use a restroom about once every 2 hours on average.
- An even mix of men and women. Women-heavy events, such as showers, may need 1 more unit.
- Accessible units: 5 percent of units, at least 1, per the 2010 ADA Standards section 213.2.
- Hand wash stations: 1 per 3 toilets when food is served.
This is the Wayne Rental Works planning method. It is not a legal requirement, and South Carolina sets no statewide event ratio. Confirm with your venue or permit office.
Porta potty chart by guest count and event length
A 100-guest party lasting up to 4 hours needs 2 standard porta potties. The same party running 5 to 8 hours needs 3 units, and 4 units with alcohol. A 300-guest festival running all day needs 10 units before alcohol. Every row below rounds up, because a short count costs more than a spare unit.
| Guests | Up to 4 hours | 5 to 8 hours | More than 8 hours | 5 to 8 hours + alcohol |
|---|---|---|---|---|
| 25 | 1 | 1 | 1 | 2 |
| 50 | 1 | 2 | 2 | 3 |
| 75 | 2 | 2 | 3 | 3 |
| 100 | 2 | 3 | 4 | 4 |
| 150 | 3 | 4 | 5 | 5 |
| 200 | 4 | 5 | 7 | 7 |
| 300 | 6 | 8 | 10 | 10 |
| 500 | 10 | 13 | 17 | 17 |
Worked examples
These 3 worked examples show the math step by step. Each one starts with guests divided by the per-unit number for the event length. Round up, then add units for alcohol. Last, check the accessible unit count and the hand wash stations.
Wedding: 150 guests, 5 hours, open bar
- 150 guests ÷ 40 per unit = 3.75, round up to 4 units.
- Alcohol: 4 ÷ 4 = 1 more unit. Total 5.
- Accessible: 5 percent of 5 rounds up to 1, so 1 of the 5 is accessible.
- Food is served: 5 ÷ 3 rounds up to 2 hand wash stations.
Many couples swap the standard units for deluxe flushing units or a 2-stall trailer.
Church picnic: 80 guests, 4 hours, no alcohol
- 80 ÷ 50 = 1.6, round up to 2 units.
- No alcohol, no addition.
- Accessible: make 1 of the 2 an accessible unit.
- Food served: 1 hand wash station.
Job site: 30 workers, 40-hour week
OSHA requires 1 seat and 1 urinal per 40 workers above 20, so the legal minimum is 1 unit. We recommend 3 units, 1 per 10 workers, so weekly service keeps up. See the OSHA porta potty rules.
Sizing questions
How many people can one porta potty handle in a day?
One standard porta potty is rated for about 200 uses before it needs pumping. At an event, that is about 50 guests over 4 hours. On a job site, it is about 10 workers for a 40-hour week.
Do women need more porta potties than men?
Women take longer per visit and cannot use the urinal, so women-heavy events such as showers and bridal parties need about 1 extra unit per 4. A pink unit for the ladies' side is a popular touch.
Is it better to have one extra unit or one too few?
One extra unit is the safer choice. A full unit before the event ends means lines, odor and an emergency service call that costs more than the spare unit would have.
How many porta potties for a 3-day festival?
Multi-day events need a service visit each night, or enough units to last. Start with 1 unit per 30 guests per day and plan nightly pumping. Call dispatch to plan the schedule.
Quote your porta potty count
Six quick fields. Wayne or dispatch calls you back with an itemized price and a delivery window.
Faster by phone: (864) 209-8751
Quote requests get a call back within 30 minutes during business hours.
- No deposit to hold a date
- Delivery, pickup and tax shown line by line
- Same-day delivery when a truck is open