How many porta potties do I need?
Plan 1 standard porta potty for every 50 guests at a 4-hour event, and 1 for up to 20 workers on a jobsite. Use the calculator below, then read the worked examples for weddings, parties and crews.
Porta potty calculator for events and jobsites
Enter your guest count and event length for an event estimate, or your crew size for the OSHA jobsite minimum. Both calculators show every step of the math so you can check it. The counts follow Lawson’s event planning method and OSHA Table D-1 for construction.
How many porta potties for 50, 100, 150 or 200 guests?
For an event of up to 4 hours, plan 1 porta potty for 50 guests, 2 for 100, 3 for 150 and 4 for 200. Add 1 unit for every 5 when alcohol is served, and add more for events longer than 4 hours. Add 1 handwashing station for every 2 toilets when food is served.
Swipe sideways to see every column.
| Guests | 4 hours | 4 hours + alcohol | 8 hours | 8 hours + alcohol | Handwash stations |
|---|---|---|---|---|---|
| 50 | 1 | 2 | 2 | 3 | 1 |
| 100 | 2 | 3 | 3 | 4 | 1–2 |
| 150 | 3 | 4 | 5 | 6 | 2 |
| 200 | 4 | 5 | 6 | 8 | 2–3 |
| 300 | 6 | 8 | 9 | 11 | 3–4 |
| 500 | 10 | 12 | 15 | 18 | 5–6 |
How the method works
- Divide guests by 50 and round up. That covers the first 4 hours.
- For each extra 4 hours (or part), add 1 unit per 100 guests.
- If alcohol is served, add 1 unit for every 5 units from steps 1–2.
- For public events, make at least 5% of each cluster wheelchair-accessible, never fewer than 1.
Worked example: a 150-guest, 5-hour wedding with a bar. 150 ÷ 50 = 3. One extra block of hours adds 150 ÷ 100 = 2 (rounded up), so 5. Alcohol adds 1 for those 5, for 6 units. A 2-stall restroom trailer plus 2 standard units also works.
How many porta potties does a construction site need under OSHA?
OSHA 29 CFR 1926.51 requires 1 toilet for 20 or fewer workers, then 1 seat and 1 urinal for every 40 workers up to 199, and 1 seat and 1 urinal for every 50 workers at 200 or more. Each standard porta potty has one seat and one urinal, so it counts as both.
| Workers | OSHA minimum | Standard units |
|---|---|---|
| 1–20 | 1 toilet | 1 |
| 21–40 | 1 seat + 1 urinal per 40 | 1 (Lawson suggests 2) |
| 41–80 | 2 + 2 | 2 |
| 81–120 | 3 + 3 | 3 |
| 121–160 | 4 + 4 | 4 |
| 161–199 | 5 + 5 | 5 |
| 250 | 1 + 1 per 50 | 5 |
Read the rule: OSHA 1926.51(c) Table D-1. Farms follow OSHA 1928.110: 1 toilet and 1 handwashing facility per 20 field workers within a quarter-mile walk.
Do I need a wheelchair-accessible porta potty?
Public events need at least 5% of the portable toilets in each cluster to be accessible, and never fewer than 1, under the 2010 ADA Standards section 213.2. A cluster of 1 to 20 units needs 1 accessible unit. Jobsite toilets used only by construction workers are exempt. Private parties are not covered but often add one.
Source: U.S. Access Board, 2010 ADA Standards. This page explains the rule; it is not legal advice. Confirm with your venue or permit office. See the wheelchair-accessible unit.
Related: event rentals, jobsite rentals and wedding restrooms.
Questions people ask before they book
These are the questions that come up on the phone before people book, answered the same way we answer them on a call. Still unsure about your date, spot or unit? Call (314) 408-7740, or see every porta potty rental question in one place.
How many porta potties for a 4-person crew?
One standard porta potty covers a crew of 1 to 20 under OSHA, so a 4-person crew needs 1.
Is 1 porta potty enough for 30 people?
One unit is enough for 30 guests at a party of up to 4 hours. For an all-day event or a weekend, book 2.
How many for a 40-person Airbnb gathering?
A 40-guest gathering of a few hours needs 1 unit; 2 if it runs all day or alcohol is served.
Do I need separate units for men and women?
Each unit has a seat and a urinal, so separate units are optional. Many hosts with 2 units sign one for each.
Ready when you are.
Tell us the address, the date and the head count. We’ll give you an itemized price on the phone and lock in delivery.