How Many Porta Potties Do I Need?
One standard porta potty serves 50 guests for a 4-hour event. Add 1 unit when alcohol is served and 1 more for every 2 hours past 4. Job sites follow OSHA: 1 toilet for 20 or fewer workers, then 1 seat and 1 urinal per 40 workers.
Porta potty calculator for events and crews
The porta potty calculator below uses the same method shown on this page: 1 unit per 50 guests for 4 hours, plus adjustments for alcohol, hours, food and public access, or the OSHA Table D-1 count for crews. Every step of the math is shown under the result.
How many porta potties do I need for a party or wedding?
A party or wedding needs 1 standard porta potty per 50 guests for 4 hours. A 200-guest wedding with a bar running 5 hours needs 4 units for the guests, plus 1 for alcohol and 1 for the extra hour: 6 units, or a 2-stall trailer plus 4 units.
| Guests (4-hour event) | Standard units | If alcohol is served | Event runs 6 hours |
|---|---|---|---|
| Up to 50 | 1 | 2 | 2 |
| 100 | 2 | 3 | 3 |
| 150 | 3 | 4 | 4 |
| 250 | 5 | 6 | 6 |
| 500 | 10 | 11 | 11 |
Adjustment steps, in whole units
- Start with guests ÷ 50, rounded up.
- If alcohol is served, add 1 unit.
- For every 2 hours past 4 hours, add 1 unit.
- For public events, make at least 5% of units wheelchair-accessible (minimum 1), per ADA 2010 Standards §213.2.
- When food is served, add 1 hand wash station per 4 toilets (our recommendation).
How many porta potties does a construction site need?
A construction site needs 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, under OSHA 29 CFR 1926.51(c) Table D-1. Each standard unit has 1 seat and 1 urinal.
Worked example: a 55-person crew. 55 ÷ 40 = 1.4, rounded up to 2 standard units. Read the full OSHA porta potty requirements for handwashing and farm rules.
When should I add more units than the chart says?
Add units beyond the chart when guests arrive all at once, such as at halftime or after a ceremony, when the site is spread out, or when many children attend. Long lines form at peaks, not averages. One extra unit costs less than a long line at a wedding.
- Two separate gathering areas more than a 2-minute walk apart: put units in both.
- Kids’ events: add 1 unit per 100 kids, because visits are frequent.
- Hot days: shade the units and schedule pickup or service promptly.
Questions renters ask
How many porta potties for 100 people?
100 people for 4 hours need 2 standard units. With alcohol, 3. If the event runs 6 hours with alcohol, 4.
How many porta potties for 200 guests?
200 guests for 4 hours need 4 standard units. Add 1 for alcohol and 1 for each 2 hours past 4.
Do I need separate units for men and women?
Separate units are optional, because each standard unit has a seat and a urinal. Events with 3 or more units often label one for women to shorten lines.
How many porta potties for 10 workers?
10 workers need 1 standard unit under OSHA Table D-1, which allows 1 toilet for 20 or fewer workers.
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