Event planning can be a complex and stressful enterprise. You want every aspect to run smoothly. This includes the ability of attendees to access restrooms without too much hassle or wait. No one likes waitingespecially to use the restroom. You may be wondering how many porta-potty rentals you need for your event.

You want to have adequate facilities so that people have a good experience without going overboard. The total tally will depend on several factors that go far beyond basic attendance numbers.

The good news is that there are some simple calculations you can do to make this determination. The guide below details what variables go into this, so that you can be certain you have adequate restrooms for your event.


While the sheer number of participants is not the only factor to consider, it is a good place to start. If you know the exact number of people who will be attending, great. If not, try to estimate the most number of people who will be there at any given time.

If you have less than 50 or 75 people at your event, one porta-potty for men and one for women should be sufficient. Add one for women if you hit 100 or go over.

Numbers get tricky as you go up, since there is more potential for overcrowding. For every extra 100 people you have beyond this starting point, add one porta-potty each for men and women. So, for an event with 200 people, you would need at least three for women and two for men.

Note that these are conservative estimates. You can always add more to be on the safe side, and the factors below can greatly impact the final tally.


Another factor to consider is how long most people will stay at your event. Notice we didn’t say how long your event lasts.

If it is a farmers market that goes all day but where most people stop in to browse only for an hour or two, you would need the minimum number of porta johns. On the other, if it is a music festival where most people will be staying the entire time, you increase the likelihood of more people needing to use the restroom.

A good demarcation for doubling your porta-potty numbers is four hours. For a regular event where people are not drinking alcohol (see below), most people will not need to use the restroom more than once every four hours. If the frequency with which people use the facilities drops below three hours, for whatever reason, you would increase the number of porta johns by about 25 percent for every hour.

Beverage Consumption

If, how much, and how long your guests will be drinking alcohol can greatly impact the number of porta-potty rentals you need. This goes for water consumption as well. If you are hosting a running event or outdoor concert in the middle of summer, where people will be drinking a lot of water, you need to take that into consideration.

An easy way to factor this variable into the calculation is to cut the window for the frequency with which people will need facilities from four to three hours. Every four hours after that, cut that window in half. So, for an eight-hour outdoor event where people are drinking alcohol, you would want to be prepared for the possibility of everyone at the event using the restroom at least once in a two-hour window.

Miscellaneous Factors

Other event details can come into play. The layout of your event is one of them. If it is a consolidated space and you have room to put all the porta john rentals together, your numbers should not change. However, if you need to have them in separate areas, this increases the likelihood of overcrowding at any one particular location.

Another example is an event such as a road race where you know the majority of participants will be using the portable restrooms around the same time (e.g., at the start of the race). For such events, doubling the number of porta-potty rentals is probably a safe estimate.

There is no one-size-fits-all calculation for such variables. However, you can still use the factors above to make pretty accurate determinations for any given location.

Also, take into account the type of event you are having. If it is an informal outdoor concert, regular porta johns may suffice.

If you are having a more formal event, consider more upscale options. These include things like a restroom trailer rental that provides running water and other amenities.

Note that there are minimum requirements you must meet for attendees that need handicap-accessible restrooms. The Americans with Disabilities Act requires you to have a ratio of one handicap-accessible porta john for every 20 portable restrooms. You must also have one for every porta-potty cluster.

Sample Calculation

As a way to further explain these estimating factors, let’s take an example. Say you have an event with 1,000 people. It is in the evening (not in the heat of the day), with no alcohol, lasts for a few hours, and has ample space to put all the portable toilet rental units in one location.

A good starting point would be our original calculation: 10 for men (one for every 100) and 11 for women (two for the first 100 then one for each 100 after that). In this scenario, you would need at least two handicap-accessible restrooms (note that they can be calculated as part of the total).

If that same event is in the middle of the summer heat, you should increase that number by at least 25 percent, or about 14 total for women and 12 or 13 for men. If attendees are drinking alcohol and the event goes all day, you might increase it again by 25 percent, to 16 or 17 for women and 15 for men.

In this scenario, you would still only need two handicapped restrooms. Although, you would need additional ones if you had more than two clusters of restrooms.

Find Porta-Potty Rentals Near You

Now that you have an idea of how to calculate how many porta-potty rentals you need for your event, you can get the ball rolling. If there are variables at your event that we did not cover, or if you need help making a final calculation for any reason, an experienced rental company can help. They likely will have seen almost every scenario and can help you make a final determination.

East Tennessee Portables is the largest portable restroom company serving this part of the state. We have the experience, expertise, and equipment to handle any work project or event. Reach out to us today with any questions or go online to get a free quote.