Calculator, OSHA & ADA cited
How Many Porta Potties Do I Need? Calculator + Charts
This porta potty calculator uses the same counting rules our Mesquite dispatch team uses on the phone, with the legal minimums cited.
- Local yard at 315 W Main St
- Same-day by noon, Mon–Sat
- Weekly cleaning included
- One itemized price
Same-day delivery covers Mesquite and towns about 15 miles out.
- Delivery areaAny Mesquite ZIP plus nearby towns — the count below works anywhere.
- Arrival timeBook big events 1–2 weeks out; single units same-day by noon.
- Right unit1 standard per 50 guests for 4 hours, or 1 per 10 workers per week. Use the calculator.
- CleaningEvents over 8 hours or 500 guests need a mid-event service; job sites get weekly service.
- Total costYour count sets the price — the quote multiplies units and shares one delivery charge.
- Events:
- 1 unit per 50 guests / 4 hrs
- Alcohol:
- +1 unit per 5 units
- Accessible:
- ≥1, or 5% per cluster
- Job sites:
- OSHA Table D-1 minimum
- Hand wash:
- 1 per 4 units; 1 per 2 with food
Porta potty calculator
The calculator has 2 modes. Enter guests and hours for an event, or workers and weekly hours for a job site. The calculator rounds every step up to a whole unit, shows its math, and separates the legal minimum from our recommendation so you can decide.
How many porta potties do I need for 100 guests?
A 100-guest event lasting 4 hours needs 2 standard porta potties. The same 100 guests for 8 hours need 4 units. Our rule is 1 unit per 50 guests for every 4 hours, rounded up. Add units for alcohol and swap at least 1 standard unit for a wheelchair-accessible unit.
| Guests | 2 hours | 4 hours | 6 hours | 8 hours |
|---|---|---|---|---|
| 25 guests | 1 | 1 | 1 | 1 |
| 50 guests | 1 | 1 | 2 | 2 |
| 100 guests | 1 | 2 | 3 | 4 |
| 150 guests | 2 | 3 | 5 | 6 |
| 200 guests | 2 | 4 | 6 | 8 |
| 300 guests | 3 | 6 | 9 | 12 |
| 500 guests | 5 | 10 | 15 | 20 |
| 750 guests | 8 | 15 | 23 | 30 |
| 1000 guests | 10 | 20 | 30 | 40 |
Adding units for alcohol
If the chart says 5 units and alcohol is served, add 1 unit. For every 5 units on the chart, add 1. A 300-guest, 6-hour wedding with a bar: the chart says 9 units, so add 2 (9 ÷ 5 = 1.8, rounded up to 2). Total: 11 units.
Adding units for a mostly female crowd
Women spend longer per visit. For showers, galas and dance recitals, ask us to swap a standard unit for a deluxe flushing unit or add one more unit per 5.
How many porta potties does OSHA require on a construction site?
OSHA requires 1 toilet for 20 or fewer workers on a construction site. Above 20 workers, OSHA requires 1 toilet seat and 1 urinal per 40 workers, and above 200 workers, 1 seat and 1 urinal per 50. Gregory Rental Works recommends 1 unit per 10 workers when units are serviced once a week.
| Workers on site | OSHA minimum (1926.51 Table D-1) | Our recommendation with weekly service |
|---|---|---|
| 1–10 | 1 toilet | 1 unit |
| 11–20 | 1 toilet | 2 units |
| 21–40 | 1 toilet seat + 1 urinal per 40 workers | 3–4 units |
| 41–80 | 2 seats + 2 urinals | 5–8 units |
| 81–200 | 1 seat + 1 urinal per 40 | 1 unit per 10 workers |
| 200+ | 1 seat + 1 urinal per 50 | Custom service plan |
Read the official text: OSHA 1926.51 Sanitation. Handwashing rules sit in 1926.51(f). Our recommendation is higher than the legal minimum because one unit for 20 workers fills up before the weekly service in Texas heat. See our construction porta potty rental page for crew servicing plans.
How many ADA porta potties do I need for a public event?
The 2010 ADA Standards section 213.2 say at least 5% of portable toilets in each cluster, and no fewer than 1, must be accessible. A 20-unit festival cluster needs at least 1 accessible unit; a 40-unit cluster needs at least 2. Accessible units need a 60-inch turning circle inside.
Source: U.S. Access Board, 2010 ADA Standards §213.2. Private backyard parties are not covered by this rule, but we still suggest one accessible unit when older relatives or guests using walkers are coming. Compare options on our ADA porta potty page.
How many porta potties do farm crews need?
OSHA 1928.110 requires 1 toilet and 1 handwashing facility for every 20 field workers, placed within a quarter-mile walk of where they work. A 45-person harvest crew needs at least 3 toilets and 3 handwashing stations. Most farms rent by the 28-day cycle during the season.
Official text: OSHA 1928.110 Field sanitation. For season-length plans, see seasonal and farm porta potty rentals.
Prefer it visual? See the porta potty count web story.
One standard unit handles about 50 guests at a 4-hour event. For a party of 20 to 40 guests, one unit is enough, and the calculator above agrees.
Porta potty count questions
These are the headcount questions we hear most often. Fifty guests, 200 guests and a 150-guest wedding come up every week. Each answer uses the same rule as the calculator: 1 unit per 50 guests per 4 hours, with alcohol and accessibility added.
How many porta potties for 50 guests?
Fifty guests at an event of up to 4 hours need 1 standard porta potty. For 6 to 8 hours, plan 2 units. If alcohol is served, still plan 2.
How many porta potties for 200 people?
Two hundred guests for 4 hours need 4 standard units. Add 1 unit if alcohol is served, and make at least 1 of them wheelchair-accessible if the event is public.
How many porta potties for a wedding of 150?
A 150-guest wedding lasting 5 hours needs 4 units by our formula (150 ÷ 50 × 5 ÷ 4 = 3.75, rounded up). Add 1 for a bar. Many couples swap these for a 2- or 3-stall restroom trailer.
Is one porta potty enough for 10 workers?
Yes. One unit with weekly service covers 10 workers on a 40-hour week. In July and August, or with 50+ hour weeks, add a second weekly service.
Do I need a hand washing station?
Yes, whenever food is served or OSHA applies. Plan 1 hand washing station per 4 toilets, or 1 per 2 toilets when food is served.
Calls get answered faster than forms
Calling (361) 213-6286 is the quickest way to lock a delivery slot, especially for same-day orders. We answer live Mon–Sat 7 AM–7 PM. Have your address, dates and headcount ready and the call takes about 4 minutes.
- What we ask: address or ZIP, delivery and pickup dates, unit type, quantity, headcount, gate or placement notes.
- What you get: one itemized price — unit, delivery, pickup, servicing, any fees — texted or emailed.
- How you pay: card by phone or a secure pay link; invoices are e-signed on your phone.
Send us your headcount
Six quick fields. We text or call back with a full price — unit, delivery, pickup and service — usually within about 15 minutes during business hours. Need it today? Call (361) 213-6286 instead; calls are faster.