How Many Porta Potties Do You Need? Chart and Calculator
Plan 1 standard porta potty for every 50 guests at an event of up to 4 hours. Longer events, alcohol and food change the count. Use the estimator first, then check the full chart and the rules for accessible units and job sites.
How many porta potties do you need for your event or crew?
Most events need 1 standard porta potty per 50 guests for up to 4 hours, and more as the event runs longer. Job sites need at least 1 toilet for up to 20 workers under OSHA rules. Enter your numbers in the porta potty estimator below for a fast count.
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Book this count: (423) 220-8808
Event math uses the standard portable sanitation sizing chart. Crew math uses OSHA 29 CFR 1926.51 Table D-1. See the full sizing guide.
What does the porta potty chart say for 50 to 1,000 guests?
The porta potty chart gives 1 unit per 50 guests for events up to 4 hours, 1 per 40 guests for 5 to 6 hours, 1 per 32 for 7 to 8 hours, and 1 per 25 beyond 8 hours. Always round up. A 200-guest, 6-hour party needs 5 units.
| Guests at the busiest point | Up to 4 hours | 5–6 hours | 7–8 hours | More than 8 hours |
|---|---|---|---|---|
| 50 | 1 | 2 | 2 | 2 |
| 75 | 2 | 2 | 3 | 3 |
| 100 | 2 | 3 | 4 | 4 |
| 150 | 3 | 4 | 5 | 6 |
| 200 | 4 | 5 | 7 | 8 |
| 250 | 5 | 7 | 8 | 10 |
| 300 | 6 | 8 | 10 | 12 |
| 400 | 8 | 10 | 13 | 16 |
| 500 | 10 | 13 | 16 | 20 |
| 600 | 12 | 15 | 19 | 24 |
| 750 | 15 | 19 | 24 | 30 |
| 1,000 | 20 | 25 | 32 | 40 |
This is the standard sizing chart used across the portable sanitation industry, including by members of the Portable Sanitation Association International (PSAI). It is a planning guide, not a law.
Count guests at the busiest point of the day, not everyone who comes and goes. Then add the adjustments below for alcohol, accessibility and hand washing.
How many extra porta potties do you need when alcohol is served?
Add 1 porta potty for every 5 units on the chart when alcohol is served, and round up. If the chart says 5 units, add 1 because alcohol is served, for a total of 6. If the chart says 8 units, add 2 for a total of 10.
| Units from the chart | Add for alcohol | New total |
|---|---|---|
| 1–5 | +1 | 2–6 |
| 6–10 | +2 | 8–12 |
| 11–15 | +3 | 14–18 |
| 16–20 | +4 | 20–24 |
Drinks make guests use the restroom more often, and lines grow fast after a toast or a band break. A bar is the most common reason an event runs short.
For a wedding with a bar, see the wedding restroom rental page for trailer and flushing options.
How many wheelchair-accessible units does an event need?
The 2010 ADA Standards, section 213.2, say at least 5% of portable toilets in each cluster, and never fewer than 1, must be wheelchair-accessible. A group of 1 to 20 units needs 1 accessible unit. A group of 21 to 40 units needs 2. These accessible units count toward your total.
| Portable toilets in one group | Wheelchair-accessible units needed |
|---|---|
| 1 to 20 | 1 |
| 21 to 40 | 2 |
| 41 to 60 | 3 |
| 61 to 80 | 4 |
This count is a legal rule, separate from the industry sizing chart above. Read the standard at the U.S. Access Board ADA Standards. Section 304 sets the 60-inch turning circle inside.
This page is a plain summary, not legal advice. The event organizer or venue should confirm the plan. Our wheelchair-accessible porta potty has a ground-level floor, a 36-inch door and grab bars. It needs a flat, firm pad about 7.5 feet square.
How many hand washing stations should you add?
Add 1 hand washing station for every 5 toilets when food is served, with a minimum of 1. An event with 8 porta potties and a food line needs 2 stations. Each station has 2 basins and about 34 gallons of fresh water, enough for roughly 500 hand washes.
Put one station near the toilets and, if you can, one near the food line. Kids' events and petting zoos need them even without food.
See sizes and placement on the hand washing station rental page.
How many porta potties does OSHA require on a construction site?
OSHA rule 29 CFR 1926.51, Table D-1, requires 1 toilet for 20 or fewer workers. With 20 or more workers, the rule calls for 1 toilet seat and 1 urinal per 40 workers. Sites with 200 or more workers need 1 seat and 1 urinal per 50 workers.
| Workers on site | Minimum under Table D-1 |
|---|---|
| 20 or fewer | 1 toilet |
| 20 or more | 1 toilet seat and 1 urinal per 40 workers |
| 200 or more | 1 toilet seat and 1 urinal per 50 workers |
Read the full text at OSHA 29 CFR 1926.51. Tennessee runs its own state plan, TOSHA, which adopts the federal construction standards. Georgia job sites fall under federal OSHA.
Each standard porta potty has a seat and a urinal in one cabin. Handwashing rules for crews that handle harmful substances are in paragraph (f) of the same rule.
What we suggest beyond the legal minimum
Our business recommendation, which is not law, is 1 standard unit per 10 workers for a 40-hour week with weekly service. Above that load, tanks fill faster and lines form at breaks. Add a second weekly visit for 10 or more workers per unit, or in July and August heat.
| Crew size | OSHA minimum (standard units) | Our suggestion with weekly service (not law) |
|---|---|---|
| 8 | 1 | 1 |
| 15 | 1 | 2 |
| 20 | 1 | 2 |
| 30 | 1 | 3 |
| 50 | 2 | 5 |
| 80 | 2 | 8 |
| 120 | 3 | 12 |
Weekly service is included on every construction porta potty rental.
How does the math work for a wedding, a crew and a festival?
Three worked examples show the method. A 150-guest, 5-hour wedding with a bar needs 5 units. A 30-worker framing crew needs 3 units with weekly service. A 300-person, 6-hour church festival with food needs 8 units plus 2 hand washing stations.
150-guest wedding, 5 hours, with a bar
- Chart: 150 guests at 5–6 hours is 1 unit per 40 guests. 150 ÷ 40 = 3.75, so round up to 4.
- Alcohol: the chart says 4 units, so add 1. Total: 5.
- Accessibility: 5% of 5 rounds up to 1 wheelchair-accessible unit, counted inside the 5.
- Food: 5 toilets ÷ 5 = 1 hand washing station.
30-worker framing crew
- OSHA minimum: 30 workers is more than 20, so 1 seat and 1 urinal per 40 workers. One standard unit covers it: 1.
- Our suggestion: 1 unit per 10 workers for a 40-hour week. 30 ÷ 10 = 3 units with weekly service.
- Summer: in July and August, add a second weekly service visit.
300-person church festival, 6 hours, with food
- Chart: 300 guests at 5–6 hours is 1 unit per 40 guests. 300 ÷ 40 = 7.5, so round up to 8.
- Alcohol: none, so no change.
- Accessibility: 5% of 8 rounds up to 1 wheelchair-accessible unit.
- Food: 8 toilets ÷ 5 = 1.6, so round up to 2 hand washing stations.
Planning a public event? The event porta potty rental page covers Friday drop-off and layout.
What other sizing questions come up?
Sizing questions usually come down to 3 things: how to count guests, what to do for small or very long events, and what is a rule versus a guideline. These 7 answers use the same chart and the same rounding as the estimator at the top of this page.
How many porta potties do I need for 100 guests at a 4-hour party?
A 100-guest party of up to 4 hours needs 2 standard porta potties by the industry chart. Add 1 more if alcohol is served, for 3 in total. If food is served, add 1 hand washing station.
Does a 30-guest backyard cookout need more than one porta potty?
One standard porta potty covers 30 guests for an event of up to 8 hours, since the chart allows 32 guests per unit at 7 to 8 hours. Serving alcohol adds 1 unit, so plan 2 if there is a bar or a cooler of beer.
Should I count guests who only stop by for part of the day?
Count the most people on site at the same time, not everyone who stops by. For an open house where 300 people come and go but only 120 are there at once, size for 120. Round up if the crowd arrives all at once, such as right after a ceremony.
Do kids count as guests when sizing porta potties?
Count children as full guests. Kids tend to make more trips, so the chart number holds up well. For kids' events with food, plan at least 1 hand washing station so small hands get real soap and water.
How many porta potties does a 3-day festival need?
A festival running more than 8 hours a day needs 1 unit per 25 guests at the busiest point. For 500 people, that is 20 units. Over 3 days, units fill up, so add a mid-event service visit. We offer those for events longer than 2 days.
What happens if I order too few porta potties?
Too few units means lines, full tanks and unhappy guests before the event ends. Call us as soon as you see a shortage. Same-day delivery works when you call by 12 PM on a weekday, and an extra service visit can buy time.
Is the porta potty sizing chart a legal requirement?
The sizing chart is an industry planning guide, not a law. The legal rules on this page are the ADA count for accessible units and OSHA Table D-1 for construction crews. Your city, park or venue may set its own count, so ask them too.