What this checker estimates
This checker estimates the chance of reaching the front of a waiting list, from your position, the places expected to become available, and how many people ahead of you are likely to drop out.
It is a heuristic rather than a probability calculation. It combines two estimates you have to supply, and the answer is only as good as they are.
Enter your details
Before you read the result
- Position should be your actual place, not an approximation. Many organisations will tell you if asked.
- Places available means genuine openings in the period you care about, not total capacity.
- Dropout rate is the proportion of people ahead of you who will withdraw, decline or become ineligible. It varies enormously between contexts.
- Many waiting lists are not first-come-first-served. Priority criteria override position entirely in some systems.
School admissions, social housing and NHS treatment lists generally allocate by defined criteria rather than by arrival order — catchment and siblings, housing need bands, clinical urgency. Where that is the case, a position number describes where you currently sit rather than a place in a queue, and it can move in either direction as others join.
How this calculator works
Effective openings against your position:
Effective openings = places available + ((position − 1) × dropout rate)
Estimated chance = effective openings ÷ position, capped at 100%The dropout term treats each person ahead of you as having that probability of withdrawing, which adds to the openings that reach you. It is a linear approximation rather than a proper probability model, and it can produce a figure above 100%, which the checker caps.
Because both inputs are estimates, the output should be read as a rough band — good, moderate or poor — rather than as a percentage to be quoted.
Worked example: twelfth on the list
Using the default figures — position 12, 8 places expected, 20% dropout ahead of you:
- Effective openings: 8 + (11 × 0.2) = 10.2
- Estimated chance: 85.0%
85% looks encouraging, and it rests entirely on the 20% dropout figure. At 10% dropout the estimate falls to 76%; at zero it is 67%. Since the dropout rate is usually a guess, the honest reading is somewhere between two thirds and six in seven — which is a useful thing to know and not the same as 85%.
Common mistakes
- Treating the percentage as precise. It rests on two estimates and moves substantially with either.
- Assuming the list is a queue. Many allocate by criteria rather than position.
- Guessing a high dropout rate. It flatters the result more than any other input.
- Ignoring that positions can move backwards. Higher-priority applicants can join ahead of you.
- Relying on one list. Where multiple applications are permitted, they are usually the better strategy.
Frequently asked questions
How do school admission waiting lists work?
By the school's published oversubscription criteria rather than by application date — commonly looked-after children first, then siblings, then distance. Your position can therefore move down if a family closer to the school joins the list. Lists are usually maintained until at least the end of the autumn term and often longer, and councils publish the criteria and previous years' distances.
What about NHS waiting lists?
Allocation is by clinical priority alongside waiting time, so a position number does not behave like a queue. Patients have rights under the NHS Constitution on maximum waiting times, and where those are exceeded there are routes to raise it with the provider or to be offered an alternative. Your GP or the hospital's patient advice service can explain your specific position.
How can I improve my chances?
Depending on the context: apply to several lists where permitted, keep your details current so you are contactable, respond promptly to any offer, and ask what the criteria actually are rather than assuming. On many lists, people are removed simply for not responding, which is part of the dropout the calculation assumes.
Should I stay on a list I am unlikely to reach?
Usually yes, where staying costs nothing — dropout is real and lists move more than people expect. The exception is where remaining on one list prevents applying elsewhere, which is worth checking rather than assuming.
Is what I enter stored?
No. Figures are processed in your browser and never transmitted or retained.
Related tools
References
- GOV.UK — school admissions appeals, social housing allocation and public service waiting times
- National Institute for Health and Care Excellence — clinical prioritisation guidance relevant to NHS waiting lists
Sources are checked at publication and can change — how I choose and check references.