Bradford Factor calculator
The Bradford Factor condenses a year of absences into one number, weighting frequent short spells far more heavily than a single long one. Enter the last 52 weeks and read the score — and, just as important, what it can't tell you.
Around here many policies suggest an informal check-in.
The same 8 days in one single absence would score just 8: the square punishes frequency, not duration.
Example trigger bands
- Low
- 0–50
- Worth monitoring
- 51–200
- Cause for concern
- 201–400
- Serious concern
- 401–600
- Critical
- 601+
There is no statutory scale. These bands mirror the trigger points most often cited in HR practice (51 / 201 / 401 / 601); every employer defines its own — in writing, applied consistently.
Method: B = S² × D over a rolling 52-week window, where S counts separate absence spells and D the working days missed. The score is a signal that a conversation may help — never a verdict on a person.
How the score works
The formula comes from the Bradford University School of Management: over a rolling period — 52 weeks in most policies — count the separate absence spells (S) and the total working days missed (D). S is squared, D is not. That asymmetry encodes the factor's one idea: many short, unplanned absences disrupt planning, cover and morale far more than one long, foreseeable one.
B = S² × D — ten 1-day absences: 10² × 10 = 1,000 · one 10-day absence: 1² × 10 = 10
Two people each miss twelve days in a year. One broke a leg once: 1² × 12 = 12. The other was out twelve separate Mondays: 12² × 12 = 1,728. Same days, two very different numbers — that gap is exactly what the formula measures, and why the score still needs human judgement.
Before you act on a score
The Bradford Factor was born in British HR practice and no law anywhere sets its thresholds. Three cautions before wiring it into policy: repeated short absences often trace back to a chronic condition or disability, and mechanical triggers can slide into discrimination — fair policies exclude disability-related, maternity and work-injury absences from the count. Health data is special-category data under GDPR article 9: record dates and a generic absence type, never diagnoses. And treat the score as the start of a supportive conversation — a return-to-work chat — not as an automatic sanction.
Frequently asked questions
What is a good Bradford Factor score?
Below roughly 50, absence looks ordinary and most policies see nothing to act on. The example triggers cited most often are 51 (informal chat), 201 (formal review), 401 (serious concern) and 601+ (critical). They're conventions, not law: each employer sets its own thresholds and should publish them in the absence policy.
Over which period is it calculated?
Almost always a rolling 52-week window: at every new absence the score is recomputed over the previous year, so old spells drop out as they age past 52 weeks. Some companies use the calendar year or the leave year instead. Any window works — what matters is using the same one for everyone.
Is the Bradford Factor fair?
It measures disruption, not honesty or health. A parent with three short child-sickness absences outscores a colleague who was away a month with a broken leg. Chronic conditions and disabilities inflate the score through no fault of the person — which is why fair policies exclude protected absences from the count, read the score alongside context, and never sanction on the number alone.
Can I discipline someone based on their score?
Not on the score alone. In most of Europe, acting on sickness absence itself is legally constrained — and where absences relate to a disability, mechanical trigger points can amount to discrimination. Use the score to spot patterns and open a conversation; let any formal step rest on a proper individual assessment, with advice where needed. This page isn't legal advice.
The data behind the score, without the spreadsheet
Bueggio HR records every absence with dates and type as your team books time off — spells and days always current, health details never stored. GDPR-first, from €1.30 per user per month.
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