Porta Potty Calculator

For 100 guests at a 4 hour event with no alcohol, order 2 units. The math: 100 guests divided by 50 gives a base of 2 units, and with the duration, alcohol, and wedding factors all at 1.0 the raw result is 2.0, so rounding up gives 2 units. Plan 1 ADA accessible unit on top of that (the 5 percent rule with a minimum of 1) and 1 handwash station (1 per 4 units).

Longer events need more capacity because guests use the facilities multiple times. This calculator multiplies the base count by a duration factor: up to 4 hours x1.0, 5 to 6 hours x1.3, 7 to 8 hours x1.5, 9 to 10 hours x1.8, and 11 hours or more x2.0. Example: 200 guests at an 8 hour event gives 200 divided by 50 equals 4 base units, times 1.5 equals 6 units.

Yes. Alcohol increases restroom traffic, and rental vendors generally recommend 10 to 30 percent more units when drinks are served. This calculator applies a x1.20 alcohol factor. Example: 100 guests for 4 hours with alcohol gives a base of 2 units times 1.20 equals 2.4, which rounds up to 3 units.

Weddings get a comfort multiplier of x1.25, which works out to about 1 unit per 40 guests instead of 1 per 50. Example: 150 guests, 6 hours, alcohol served. Base is 150 divided by 50 equals 3, times the 6 hour factor 1.3 equals 3.9, times the alcohol factor 1.2 equals 4.68, times the wedding factor 1.25 equals 5.85, which rounds up to 6 units. Add 1 ADA accessible unit and 2 handwash stations.

Plan at least 1 ADA accessible unit for every 20 standard units, which is the commonly cited 5 percent rule, with a minimum of 1 accessible unit at any public event. This calculator uses the larger of 1 and 5 percent of total units, rounded up. The path to the accessible unit must also be level and free of curbs, steps, or other barriers.

A common rule of thumb is 1 handwash station per 4 portable toilet units, with a minimum of 1 station. This calculator applies that rule. Handwash stations are especially recommended for events with food service and for construction sites, where OSHA expects adequate washing facilities alongside toilets.

OSHA 29 CFR 1926.51 Table D-1 requires: 20 or fewer workers, 1 facility; 21 to 199 workers, 1 toilet seat plus 1 urinal per 40 workers; 200 or more workers, 1 toilet seat plus 1 urinal per 50 workers. Because a standard portable unit provides one seat and no urinal, the seat plus urinal pair converts to 1 portable unit per 20 workers. So 40 workers need 2 units, while OSHA literally counts 1 seat plus 1 urinal. Always confirm with local rules, which can be stricter.

Service at least once per week, and twice per week when more than 10 workers share a single unit. Billing weeks round up with a 1 week minimum. Example: 40 workers with 2 units for 30 days means 20 workers per unit, so servicing is twice per week; 30 days is 5 billing weeks, giving 10 service visits per unit, 20 visits total.

Typical United States pricing is 100 to 200 dollars per standard unit per day, 50 to 100 dollars flat for delivery and pickup, and 35 to 60 dollars per servicing visit per unit, with ADA units carrying a daily premium. Worked example: 6 units for 2 days at 125 dollars per day is 1,500 dollars; 1 ADA unit at a 40 dollar premium for 2 days is 80 dollars; servicing at 6 units times 1 visit times 45 dollars is 270 dollars; plus 75 dollars delivery gives an estimated total of 1,925 dollars.

Choose standard portable units for construction sites, casual outdoor events, and tight budgets. Choose a restroom trailer with flushing toilets and sinks for weddings, VIP areas, and multi day events where power and water hookups are available. Trailers cost several times more per day but sharply improve guest comfort. This calculator sizes standard units; for a trailer, ask the vendor how many stalls equal your unit count.

Book 2 to 4 weeks before your event or project start date. During peak season, which is late spring through early fall in most regions, and around major local festivals, book 6 to 8 weeks ahead. Construction projects should schedule units to arrive before the first crew day so the site is compliant from day one.

Place units on level ground with truck access for delivery, servicing, and pickup. Keep them near activity areas but downwind of food service, spaced out for large crowds rather than clustered in one spot. Maintain a clear accessible path to the ADA unit, add lighting for evening events, and on jobsites keep units within a short walk of the work area so crews actually use them.

No. This tool sizes portable restrooms only: unit counts, ADA units, handwash stations, OSHA construction requirements, servicing, and rental cost. Tent sizing is a separate job with its own math for seating styles and floor plans, covered by our tent size calculator.