Sizing guide + calculator
How Many Porta Potties Do I Need?
Enter guests and hours, or crew size, and get a unit count with the math shown. Tables below cover the same numbers for quick reference.
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How many porta potties for an event?
An event needs one porta potty for every 300 guest-hours, rounded up. Multiply guests by event hours and divide by 300. A 150-guest, 5-hour event needs 3 units. Serving alcohol adds 1 unit for every 5, with a minimum of 1, so that event needs 4 with a bar.
The method is our own planning rule, built from tank capacity: a standard unit handles about 200 uses before service, and guests visit roughly every 2 to 3 hours. It is the same rule our dispatcher uses on the phone.
Porta potty calculator
Porta potties needed by guest count and hours
For a 4-hour event, 100 guests need 2 porta potties, 200 guests need 3, and 300 guests need 4. For an 8-hour event, those numbers rise to 3, 6 and 8. Add units for alcohol, and include at least one wheelchair-accessible unit for public events.
| Guests | 2 hrs | 4 hrs | 6 hrs | 8 hrs | 10 hrs |
|---|---|---|---|---|---|
| 50 | 1 | 1 | 1 | 2 | 2 |
| 100 | 1 | 2 | 2 | 3 | 4 |
| 150 | 1 | 2 | 3 | 4 | 5 |
| 200 | 2 | 3 | 4 | 6 | 7 |
| 300 | 2 | 4 | 6 | 8 | 10 |
| 500 | 4 | 7 | 10 | 14 | 17 |
| 1,000 | 7 | 14 | 20 | 27 | 34 |
Adjustments, step by step
- Alcohol: if the table says 5 units, add 1 (one per 5, rounded up, minimum 1).
- Accessibility: at least 5 percent of units in each cluster must be wheelchair-accessible, minimum 1 (2010 ADA Standards §213.2). Among 4 units, 1 should be accessible.
- Food: add 1 hand-wash station for every 4 toilets, minimum 1.
- Mostly women: add 1 unit.
How many porta potties for a construction crew?
A California construction crew needs at least one toilet per 20 workers of each sex (Title 8 §1526) and one washing station per 20 workers (§1527). With weekly service, plan one standard porta potty per 10 workers on a 40-hour week so the tank does not fill before service day.
| Workers | Cal/OSHA toilets | Washing stations | Units, weekly service | Units, twice-weekly |
|---|---|---|---|---|
| 1–10 | 1 | 1 | 1 | 1 |
| 11–20 | 1 | 1 | 2 | 1 |
| 21–30 | 2 | 2 | 3 | 2 |
| 31–40 | 2 | 2 | 4 | 2 |
| 50 | 3 | 3 | 5 | 3 |
Minimum counts assume one sex; mixed crews are counted separately for each sex. See the official Title 8 §1526. More detail is on the construction page and in our Cal/OSHA guide.
Got your number? Get the price.
Send the unit count from the calculator with your ZIP and dates. We confirm the mix and send an itemized quote.
Sizing questions
Do kids count as guests?
Count children over 5 as full guests. Young kids use the restroom often, so do not reduce the number for a family event.
Should I add units if most guests are women?
When most guests are women, add 1 unit to the result, because urinals in standard units go unused. The same applies to baby showers and bridal events.
How many units for an overnight or multi-day event?
Multi-day events need the daily number of units plus a service visit each day, or about one more unit per 50 campers. Call for a service plan so tanks never fill during the event.
Want a second opinion on the count?
Call and describe the event. We will size it with you in two minutes.
A real person answers Mon–Sat, 7 AM–7 PM. Written quotes by text in about 15 minutes.