Wedding washroom calculator.
Enter your guest count, how long the night runs, and the bar. The calculator uses the same rule of thumb as our wedding washroom sizing guide, shows the arithmetic, and tells you straight whether one two-stall trailer covers it.
By the rule of thumb
Stalls3
3 stalls to bring in after venue toilets
By the plain one stall per 50 guests rule, one two-stall trailer covers this guest count. The bar takes the rule of thumb one stall past it, so send us the timeline.
One trailer gives you two stalls. If the venue has a building with washrooms guests can use, add them to the venue toilets field; if not, send us the headcount and timeline and we will talk through the plan.
A crowd that is mostly women queues sooner than the average. There is no reliable number for how much, so round up: when the count is close, lean toward the next stall.
The working
- One stall per 50 guests for a four to six hour event: 100 guests divided by 50 guests per stall is 2 stalls.
- Alcohol is served, so add about 20 percent: 2 times 1.2 is 2.4.
- Round up to whole stalls: 3 stalls.
- No venue toilets counted, so all 3 stalls come in.
A rule of thumb, not a guarantee. Peak moments, like right after the ceremony and after dinner, decide how the line feels. Source: Stahla, "What size of restroom trailer do I need?".
The numbers at a glance.
Stalls by the rule of thumb, rounded up, with no venue toilets counted. One per 50 guests for up to six hours, one per 40 for a dinner reception that runs into the night, and about 20 percent more when alcohol is served.
Under four hours uses the same numbers as four to six. The source gives no separate figure for a shorter event, which can need less.
Source: Stahla, "What size of restroom trailer do I need?". How we apply it: the wedding washroom sizing guide.
| Guests | Up to 6 hours | Into the night | ||
|---|---|---|---|---|
| No alcohol | Alcohol served | No alcohol | Alcohol served | |
| 50 | 1, one trailer covers it | 2, one trailer covers it | 2, one trailer covers it | 2, one trailer covers it |
| 75 | 2, one trailer covers it | 2, one trailer covers it | 2, one trailer covers it | 3 |
| 100 | 2, one trailer covers it | 3 | 3 | 3 |
| 125 | 3 | 3 | 4 | 4 |
| 150 | 3 | 4 | 4 | 5 |
| 200 | 4 | 5 | 5 | 6 |
| 250 | 5 | 6 | 7 | 8 |
| 300 | 6 | 8 | 8 | 9 |
Circled counts fit one two-stall trailer.
Shaded: your answers in the calculator.
Calculator questions.
The full reasoning is in the sizing guide. Choosing a venue? The venue guide notes what each venue's own website says about washrooms.
How do you work out how many toilets a wedding needs?
Start with about one stall for every 50 guests over a four to six hour event. For a full dinner reception that runs into the night, some sizing guides divide the guest count by 40 instead. Add about 20 percent when alcohol is served, round up to whole stalls, then take away any venue toilets guests can actually reach.
Is one two-stall washroom trailer enough for 100 guests?
For a four to six hour wedding with no alcohol, yes: 100 guests divided by 50 is two stalls. A bar or a reception that runs into the night takes the rule of thumb to three, so send us your timeline and we will tell you straight whether one trailer covers it.
Can we count the house bathroom at an acreage wedding?
Treat it as a backup, not the plan. One bathroom on a household septic system is not built for a wedding crowd. Count only toilets guests can reach and use during the event, such as a venue building with real plumbing.
Send the count and the timeline.
We will tell you straight whether one two-stall trailer covers your wedding, usually within a day. Quoted for your date and venue.
Now bookingSummer 2027