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Staff cost calculator: wage cost per child-hour and per play session

A monthly wage bill tells you nothing about the hour it was spent in. This page turns the staff on shift, their pay, your opening hours and the children on the floor into three figures: wage cost per opening hour, per child-hour, and for one child's session. In PlayAreaOS the rota and the pay run behind those numbers already sit together.

Last reviewed September 4, 2026

The formula

hourly pay per person        = hourly pay, or monthly pay / paid hours per month
loaded hourly pay            = hourly pay x (1 + on-costs % / 100)
wage cost per opening hour   = staff on shift x loaded hourly pay
wage cost per opening day    = wage cost per opening hour x opening hours per day
children on the floor        = average children, or capacity x utilisation % / 100
wage cost per child-hour     = wage cost per opening hour / children on the floor
wage cost per child session  = session length (hours) x wage cost per child-hour
children per staff member    = children on the floor / staff on shift
staff needed at your ratio   = children on the floor / your ratio   (rounded up to whole people)
Your numbers
A label for the results and nothing more: AED, SAR, USD or any text you like.
People you pay to be in the building in a typical opening hour: floor, desk, café, party host. For floor coverage alone, run it again with floor staff only.
The average across the people on shift. Leave blank if you pay monthly and fill in the two fields below instead.
Average monthly salary. Used only when hourly pay is blank.
The hours that monthly salary buys under your own contracts. Take the weekly hours you contract for, multiply by fifty-two and divide by twelve. Used with monthly pay.
Optional. Any provision you make for end-of-service, insurance or visas, as a share of pay. Your accountant's figure; this page suggests none.
How long the floor trades on the kind of day you are looking at. Needed for the cost per opening day.
The usual number playing in an opening hour. Leave blank to work it from capacity and utilisation below.
The figure your regulator, insurer or fire officer set. Used with utilisation when the average above is blank.
The share of capacity that is usually filled across the opening day.
Your standard session, for example 1.5 or 2. Needed for the wage cost of one child's session.
Optional. The supervision ratio your regulator or insurer gave you, as children per person. Nothing on this page suggests a figure.

Fill in what you know and press Calculate. Everything stays in this tab: the page stores nothing you type, makes no network call and asks for no account.

What is wage cost per child-hour?

Wage cost per child-hour is what you pay in wages for one hour of opening, divided by the children on the floor in that hour. It is the labour slice of the wider cost per child-hour. Labour earns its own line as the one large cost that moves week by week: rent is the same on a wet Tuesday as on a Saturday, but the roster need not be.

Per opening hour is what being open costs in people before a child arrives; per child-hour is what each child costs in supervision for each hour they stay; and the third multiplies that by your standard session length, which is the figure to set beside the session price and the month's labour cost percentage.

Who counts as staff on shift?

For the cost of an opening hour, count everyone paid to be in the building during it: floor supervisors, the desk, the café counter, the party host, the manager in the back office. If you work the floor yourself without drawing a wage, add a notional hourly figure for your own hours, or the result will flatter the business.

The coverage line is narrower, because a ratio only applies to the people actually watching the children, so a desk shift or a café shift stays out of that count. Run the page twice: everyone on shift for the money, floor staff only for the coverage. The staff-to-child ratio guide sorts the posts that count towards supervision from those that never do.

How do you turn monthly pay into an hourly figure?

Most venues pay a monthly salary rather than an hourly rate, so the page takes either. Leave the hourly field blank, enter the monthly pay and the paid hours it covers, and the page divides one by the other.

The on-costs field carries whatever loads on top of pay, as a percentage of your own: end-of-service provision, medical insurance, visa and permit costs, anything your accountant adds to the wage bill. This page applies no rate of its own and works out no statutory amount; left empty, the field returns bare pay. End-of-service and the air ticket are payroll work, on your venue's own figures.

Why is the ratio yours to enter?

No software vendor can tell you how many children one adult may supervise. That figure comes from whoever licenses your venue and from your insurer, and it may differ by age band and by zone. The field starts empty, the sums run without it, and the illustrative default is a placeholder. It is not anybody's rule.

Enter a ratio and two lines appear beside the money: the children each person on shift covers at your average, and the people the ratio demands for that many children, rounded up to whole people. A roster above that minimum is normal; the surplus is your desk, your break cover and your slack, and each of those is a choice you should be able to name.

What do the weekday and weekend answers tell you?

Split the week into bands and run the page for each rather than for an average day; a roster that barely changes while the children on the floor multiply several times over is where the wage cost hides. Weekday and weekend results side by side argue for rostering by the hour and for the off-peak pricing the session pricing guide works through.

Illustrative only. Five people at a loaded 27.50 an hour cover an average of 30 children: 137.50 an hour, 4.58 per child-hour, 9.17 for a two-hour session — the figures the defaults button loads. On Saturday the same five cover 60: 2.29 per child-hour, 4.58 for the same session. Every figure here is invented; none was measured anywhere.

The edges of this page

It counts wages only; rent and consumables belong to the break-even calculator. It treats the opening hour as an average, so run it per hour band rather than trusting the mean. It will never build a rota, and it states no legal figure of any kind: no ratio, no capacity, no on-cost rate. Your capacity is your regulator's number; the capacity planner turns it into sessions per day.

Running it on measured figures instead

Both halves of the sum are already in PlayAreaOS. The staff rota holds who is on shift, branch by branch, with expected demand shown beside the shifts you planned; staff clock in with a location check; and payroll follows the wage bill month by month. On the other side, the reports give the sessions and the minutes of play sold over any range, and occupancy gives the children on the floor. Minutes sold divided by sixty are your child-hours; the wage bill divided by those is this page's answer, measured rather than assumed.

Questions

Should the desk and café staff be included in staff on shift?

For the wage cost of an opening hour, yes: everyone you pay to be in the building during that hour, whatever they are doing. For the coverage line, which sets children against your ratio, only the people watching the floor belong in the count, so run the page twice with the two counts and keep both answers.

Is the children-per-staff ratio on this page a legal figure?

No. The field is empty until you type into it, and the illustrative default is a round placeholder chosen to keep the sums simple. Your supervision ratio is set by whoever licenses the venue and by your insurer; where the two differ, the stricter one applies. This page states no ratio; the one that governs you comes from your licence and your insurer.

How do I enter people who are paid a monthly salary?

Leave hourly pay blank, then fill in monthly pay and the paid hours that salary covers each month; the page divides one by the other to reach an hourly figure. Where people on the same shift are paid differently, use the average, or run the page once per pay grade and add the hourly costs together.

Why does the wage cost per child-hour swing so much between days?

Because the roster is largely fixed while the children are not. A morning with three people on shift and six children costs many times more per child-hour than a Saturday afternoon with the same three people and forty children. Run the page for each band of the week separately; the swing is the case for rostering by the hour and for off-peak pricing.

Where do the wage bill and the child-hours come from?

Both come out of PlayAreaOS. Payroll follows the wage bill month by month, and the reports give the minutes of play sold over any range, which divided by sixty are your child-hours. Put one over the other, or type the two figures into this page and let it do the rest.

Is anything I type here saved or sent anywhere?

No. The page is static and runs entirely in your browser: it stores nothing you type, no network call carries them, and there is no account to sign into. Close the tab and the figures are gone.

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