Event porta potty calculator
Estimate only, based on 1 unit per 50 guests for a 4-hour event, adjusted for length, alcohol (+20%) and heat (+10%). ADA count uses 5% per cluster, minimum 1, for public events. Call (602) 595-7860 to confirm for your venue.
How many portable toilets per person?
There's no single "per person" number, because it depends on how long people stay. The two standards used in the US are:
| Setting | Rule | Example |
|---|---|---|
| Events | 1 unit per 50 guests for about 4 hours | 200 guests, 4 hours = 4 units |
| Job sites (OSHA) | 1 toilet for up to 20 workers | 18-person crew = 1 unit minimum |
| Job sites, 20+ workers | 1 toilet seat and 1 urinal per 40 workers | 60 workers = 2 seats + 2 urinals |
| Job sites, 200+ workers | 1 toilet seat and 1 urinal per 50 workers | 250 workers = 5 of each |
A quick way to sanity-check an event: one unit handles roughly 200 to 250 uses before it needs service, and most guests use a restroom about once every two hours.
Quick reference: guests to units
| Guests | 4-hour event | 8-hour event |
|---|---|---|
| Up to 50 | 1 | 2 |
| 100 | 2 | 3 |
| 150 | 3 | 5 |
| 250 | 5 | 8 |
| 500 | 10 | 15 |
Without alcohol. Add about 20% if alcohol is served, and more for summer events. These match the calculator above.
Event rules of thumb
- Baseline: 1 unit per 50 guests for about 4 hours
- Longer events: add capacity as hours increase, or schedule mid-event service
- Alcohol: about 20% more
- Heat: more water means more trips. See summer tips.
- Accessibility: at least one ADA unit per cluster for public events
- Handwashing: a station for every 3–5 toilets, plus one at each food area
Construction sites
Job sites follow OSHA 29 CFR 1926.51, not event math. The minimum is 1 toilet for 20 or fewer workers. With 20 or more workers, it's 1 toilet seat and 1 urinal per 40 workers, and with 200 or more, it's 1 of each per 50. Full details are in our OSHA guide, and service options are on the construction porta potty page.
Layout for large events
Several small clusters beat one big one. Put restrooms near entrances, near food and drink, and at the far end of the venue, each with a handwashing station and an accessible unit. Keep clusters on firm, level ground with a clear route. Plan for the service truck to reach them for multi-day events.
Want us to check your numbers?Call with your headcount, hours and venue. We'll confirm the right setup.
(602) 595-7860Common questions
How many portable toilets are needed per person?
For events, plan on one unit per 50 guests for about 4 hours, and add capacity for longer events, alcohol or hot weather. For job sites, OSHA requires one toilet for up to 20 workers, then one toilet seat and one urinal per 40 workers above that.
How many porta potties do I need for 100 guests?
For a 4-hour event, about 2. With alcohol or a longer event, plan on 3. Add a handwashing station if food is served.
How many porta potties for 500 people?
Roughly 10 for a 4-hour event, and more for longer events or when alcohol is served. Split them into clusters, and include ADA units if the event is public.