How Many Keyholders Does a Team of 10 Need to Open and Close Every Day?
Opening and closing a site 365 days a year with four keyholders in a team of 10 leaves about 2.7 days short; three keyholders leave 16.
Four. A site that opens and closes every day needs a keyholder for each, and if policy says they cannot be the same person, that is two keyholders every day of the year. Three holders are short on about 16 days a year, because a single absence is all it takes; four holders are short on about 2.7, and five on 0.4. Across 365 days the difference between three and four keyholders is the difference between a problem most months and a problem most years.
Each extra holder, and what it buys
The rule says 2 keyholders present on every day. Each holder is absent on about 12.6 percent of rostered days. This is how many days a year fall short at each holder count.
Holding exactly 2 is a coin flipped every day. The first spare holder removes most of the exposure; the second removes most of what is left. On these assumptions, 5 holders bring the expected shortfall to one day a year or fewer, and 6 to one a decade.
How many are actually present
With 4 holders, the average day has 3.49 present. Averages do not break rosters; the days with fewer than 2 do. Across 365 days a year, this is how the year is expected to distribute.
What is hard about this one
Keyholding is the qualification that teams under-count most consistently, because it is not a course and it does not feel like cover. It feels like trust. A team of 10 typically has the manager, the deputy and one long-serving person with keys, and that is three holders for a two-per-day requirement, which the model puts short on about 16 days a year. On those days the manager opens and closes, which is a twelve-hour day that the roster did not plan and the manager does not log, so the 16 days are invisible until the manager leaves and the count becomes two.
Every day of the year is the other thing about keyholding. Most qualifications on this site are needed on working days; keys are needed on all 365, including the ones when the manager and the deputy are on holiday at the same time because they booked around the same school term. The four-holder arithmetic, 2.7 short days, assumes their absences are independent. A team where two keyholders always take the same fortnight is running on two holders for two required for that fortnight, which is the 86.5-day rate, compressed into the worst two weeks of the year.
Four holders also changes what opening and closing costs the rest of the roster. With three, the remaining holders cannot be given the same day off as each other, and their leave requests are quietly constrained by a rule nobody wrote down. With four, two can be off and the site still opens and closes. The fourth set of keys is not about the 13 days it saves; it is about the leave that the other three can finally take without negotiating with each other first.
Move the requirement, move the answer
The holder count is usually the thing being argued about. The requirement itself is the other lever, and it is worth knowing what the same 4 holders buy if the rule were one looser or one stricter.
| Required present | Covered | Short days a year |
|---|---|---|
| 1 | 100% | 0.1 |
| 2this page | 99.3% | 2.7 |
| 3 | 91.9% | 29.4 |
What this assumes, and where it is generous
These figures treat each holder as independently likely to be absent, which is the assumption most favourable to the roster. Holders are rarely independent: the two people who did the course together take the same school holidays, a certificate that lapses removes someone for the weeks it takes to rebook, and the person who is always asked to cover is the one most likely to be off sick. Treat every number here as the best case.
Only a valid certificate counts. A holder whose certificate has lapsed is a zero in this arithmetic for as long as the renewal takes, so the practical holder count is often one lower than the roster believes, and the row above the one you planned for is the one you are actually living on.
The absence share is 25 days of paid annual leave and 8 days of average sickness per person across 261 working days, which is 12.6 percent of rostered days. Both inputs vary by country; the relief factor library carries sourced figures for 17 of them. Swap your own in and the shape of the ladder holds even as the counts move.
What to do with this
Issue keys to four people, not three, if opening and closing are two different people every day. Three is short on about 16 days a year; four on 2.7.
Block two keyholders from booking the same week, because the model assumes they do not, and two holders for two required is short on about 86.5 days a year.
Write keyholding into the roster as a requirement, not a trust arrangement, so that the days the manager covers both ends are counted rather than absorbed.
How long the certificate itself stays valid, and how it is renewed: SIA licence (United Kingdom, 3 years).
The holder count on this page only works if it is the count of people whose certificate is valid today. Keeping that record current, who holds what, at which level, and until when, is what the Skills tab in Soon is for.
Common questions
- How many keyholders does a team of 10 need?
- Four, if the site opens and closes every day and the opener and closer must be different people. Three keyholders are short on about 16 days a year, because any one absence breaks the rule; four are short on about 2.7; five on 0.4. If the same person may open and close, the requirement drops to one per day and two or three holders suffice.
- Is three keyholders not enough?
- Not for two per day, every day. With three holders, one is away on about a third of days, and on each of those the remaining two must both be in. The model expects that to fail on about 16 days a year, usually covered by a manager working both ends of the day.
- Why does it matter that keys are needed 365 days a year?
- Because leave and sickness do not stop at weekends, and the two weeks when the manager and deputy are both away are the two weeks the site is most exposed. Across 365 days rather than 261, every rate on the ladder produces more short days, which is why keyholding needs a spare more than a weekday-only qualification does.
Other qualifications
1 required, 3 held
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