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Absence

Holiday accrual and the Bradford Factor, done for you

July 2026 · 6 min read

Two calculations sit underneath every well-run absence record, and most spreadsheets do neither. The first is holiday entitlement: how much paid leave a person has actually earned. The second is a way to read sickness that does not reward the quiet absentee - which is what the Bradford Factor is for. Get both right and a leave sheet stops being a list and starts being a management tool.

Here is what each one means, why they matter, and how to stop typing them by hand.

How UK statutory holiday actually accrues

The statutory floor in the UK is 5.6 weeks of paid holiday a year. The word "weeks" is the part people trip over, because a week is not five days for everyone. Entitlement is 5.6 times the number of days a person normally works in a week, which is why a part-timer accrues pro-rata rather than getting a flat 28 days like everyone else.

A few worked figures make it concrete. Someone on five days a week earns 5.6 x 5 = 28 days, which is where the familiar "28 days" comes from - and it is the statutory cap, so full-timers stop there. Someone on three days a week earns 5.6 x 3 = 16.8 days. Someone on four earns 22.4. Nobody should be reverse-engineering those numbers in their head at the point a holiday request lands.

The statutory 5.6 weeks is a minimum, not a target. Plenty of employers grant more for long service or as a benefit, so the entitlement figure has to stay editable rather than locked to a formula you cannot override. A tracker that computes the pro-rata default and then lets you type over it is doing the arithmetic and respecting your policy at the same time.

Entitlement is 5.6 weeks times contracted days per week, capped at 28. Everything above that is a policy choice, not a calculation.

What the Bradford Factor measures, and why

Total sick days is a blunt number. It treats one person off for a fortnight with a broken leg exactly the same as another who takes ten scattered single days across the year, and those are very different management problems. The Bradford Factor exists to tell them apart.

The formula is deliberately simple: the number of separate absence spells, squared, multiplied by the total days lost. Squaring the spell count is the whole trick - it weights frequency far more heavily than duration, because frequent short absences are the more disruptive and the more manageable pattern.

The numbers are stark once you run them. Ten separate one-day absences score 10 squared times 10, which is 1,000. One single ten-day absence scores 1 squared times 10, which is 10. Same ten days lost, a hundredfold difference in score - because the first pattern is the one worth a conversation. Banding the result Green, Amber, Orange and Red, with thresholds you set to match your own policy, turns that score into a trigger point rather than a raw figure to interpret.

None of this is a disciplinary verdict. The Bradford Factor is a flag that says "look here", nothing more. What you do next is a matter for a fair process and, where it involves health, appropriate care and advice.

The heatmap that a running total hides

Even a good Bradford score is a single number per person. What it cannot show you is when absence clusters. A month-by-month grid, coloured by how much absence lands in each cell, surfaces patterns that a column of totals will never reveal: the person who is reliably off every school holiday, the team that dips every January, the slow drift that started three months ago. Colour does in a glance what a pivot table does in five minutes.

Put the three together - a pro-rata entitlement figure, a Bradford score banded to your policy, and a heatmap across the year - and you can walk into an absence review already knowing who to talk to and why. That is the difference between recording absence and actually managing it.

Stop doing the arithmetic by hand

Every calculation above is mechanical, which means a workbook can carry it for you. Log a start and end date and the working days count themselves. Enter the spells and the Bradford score bands itself. Add each person's contracted days and their entitlement lands pro-rata. The moment the maths is automatic, the record stays current, because nobody has to remember to update it - and a current record is the only kind worth keeping.