A simple check-in queue model for your event
You have a guest list and an arrival window, and you want a sensible starting number of desks.
The short answer
A simple queue model multiplies desks by the minutes available and by a realistic utilisation share, then divides by seconds per guest. The result is how many guests the desks could process in that window if arrivals were spread evenly.
Real arrivals bunch up, so treat the figure as a planning aid, not a prediction of waiting time or a crowd-safety assessment. Use the check-in throughput estimator for the arithmetic and test it with a timed practice run.
The formula and its assumptions
Capacity equals desks, times available seconds, times utilisation, divided by service seconds per guest. Utilisation allows for pauses, scanner delays and staff changeovers; choose it yourself and record why.
The formula assumes guests arrive at an even pace and each takes about the same time. Neither is true in practice, which is why the output is illustrative.
Inputs you need to gather
| Input | Where it comes from | Caution |
|---|---|---|
| Expected arrivals in the window | Registered numbers and the arrival-wave view in arrival-wave planning. | Use a range, not a single figure. |
| Window length | Doors-open time to programme start. | Check the venue's access time, not just your own schedule. |
| Desk count | Your layout from desk layout. | Count only desks with a trained person. |
| Seconds per guest | A timed practice run with real badges and the real scanner. | Time exceptions separately from the normal case. |
| Utilisation share | Your own assumption, written down. | Do not borrow a figure from another event without checking it. |
How to read the result
- If capacity is clearly above expected arrivals, the desk plan has headroom for bunching.
- If capacity is close to arrivals, add desks, stagger entry, or open earlier in agreement with the venue.
- If capacity is below arrivals, a backlog will form. Decide in advance where it will wait, and have the venue approve that space.
- Run the numbers again for the busiest ten minutes, not only the whole window.
What the model leaves out
It does not cover crowd density, walkway width, queue length limits or exit routes. Those belong to the venue and competent parties. Ask them what waiting numbers the space can take, and plan to stay below that.
Worked example · Fictional example
Four desks against a busy half hour
Fictional organisation and figures, illustrative only.
A fictional professional-learning team expects about 200 delegates in the 30 minutes before the opening keynote. They plan four desks, a 40-second average service time and 80 percent utilisation.
Capacity is 4 desks x 1,800 seconds x 0.8 divided by 40 seconds, which is 144 guests. About 56 would still be waiting at the end of the half hour. With six desks the same arithmetic gives 216, so they ask the venue about space for two more desks and agree an earlier door time.
Use this yourself
Queue model worksheet
Fill this in before the practice run, then update it with the timed figures.
| Line | Your figure | Note |
|---|---|---|
| Expected arrivals in the window (range) | Source of the number: | |
| Window length in seconds | Doors time agreed with venue: | |
| Number of staffed desks | Trained people available: | |
| Average seconds per guest (timed) | Date of practice run: | |
| Utilisation share | Reason for this figure: | |
| Capacity = desks x seconds x utilisation / service seconds | Illustrative only | |
| Shortfall or headroom against arrivals | Action if short: | |
| Where a backlog would wait | Venue approval: |
Handle it in-house, or bring in help?
Your team can usually handle this when
- You can run a timed practice with the real scanner and badges.
- Arrivals are spread across a long window and numbers are modest.
- The venue has confirmed where guests may wait.
Outside planning help earns its fee when
- Most guests arrive in a short burst before a fixed start.
- Several guest types with different checks share the same desks.
- The venue needs a documented plan for waiting space before it will agree the doors time.
Need the queue plan agreed, not just calculated?
A conference project lead can run the practice timing, adjust desk numbers and doors time with the venue, and brief the desk team on what happens when the numbers are exceeded. Share your arrival expectations to discuss the scope.
Questions organisers ask
Can the estimate tell us how long guests will wait?
No. It shows whether desk capacity is above or below arrivals under even-flow assumptions. Waiting time depends on how arrivals bunch up and how long each guest takes.
What utilisation figure should we use?
Choose a figure that allows for pauses and delays, and write down why. Check it against your practice run rather than copying another event's number.
How do we decide how many guests may queue?
Ask the venue and the competent parties what the space can take. This page does not give a safe waiting number.
Related resources
Content record: Draft. Written from the cited sources and checked by automated rules; not yet independently reviewed.