Bradford Factor Calculator
Updated August 2026 · Free · No sign-up
Calculate the Bradford Factor — the S² × D absence score that weights frequent short absences far more heavily than one long illness — with the trigger thresholds employers use and what your score means.
Quick answer: Bradford Factor = Spells² × Days (S × S × D) over a rolling 12 months. Ten one-day absences score 10 × 10 × 10 = 1,000; one ten-day illness scores 1 × 1 × 10 = 10 — same days off, 100x the score. Common triggers: ~50 informal chat, ~200 formal review, 400-500+ disciplinary territory.
The Formula and Its Logic
B = S² × D — spells (separate absence occasions) squared, times total days absent, usually over a rolling 52 weeks. Squaring the spells encodes the operational truth that unpredictable short absences disrupt more than planned long ones: each new occasion forces same-day cover, missed handovers, and scheduling chaos, while a single long sickness gets managed once. Whether that logic is fair is exactly the controversy covered below.
Worked Examples
Example 1 — the classic contrast. Ten Mondays off sick: 10² × 10 = 1,000. One 10-day flu: 1² × 10 = 10. Identical days lost; two orders of magnitude apart.
Example 2 — typical year. Four spells totalling 7 days: 4² × 7 = 112 — past most informal-chat triggers, under formal-review ones.
Example 3 — the trigger cliff. An employee at 3 spells/6 days (54) takes one more two-day absence: 4² × 8 = 128 — one occasion more than doubles the score. The squared term makes every additional spell disproportionately expensive.
Common Trigger Bands
| Score | Typical employer response |
|---|---|
| 0-50 | No action — normal life |
| 51-200 | Informal conversation / monitoring; return-to-work chats |
| 201-449 | Formal absence review; improvement targets |
| 450-649 | Written warning territory in strict policies |
| 650+ | Final warning / capability process |
Bands vary by employer — the numbers above are the commonly cited UK pattern, not law. Policies should state their own triggers.
The Fairness Problem (and the Legal Line)
Bradford's blind spot is why people are absent. Applied mechanically it punishes chronic conditions (migraine, asthma, IBS — many short spells by nature), and that collides with disability law: under the UK Equality Act, disability-related absences generally must be discounted or triggers adjusted as a reasonable adjustment; pregnancy-related absence is protected outright. Tribunals have repeatedly criticized robotic trigger enforcement. A defensible policy uses Bradford to flag conversations, never to auto-discipline — the score starts the inquiry into causes; it must not end it.
Using It Well (Managers)
- Return-to-work interviews beat the score: the best-evidenced absence intervention is a supportive conversation after every spell — Bradford just tells you where patterns are forming.
- Adjust for protected causes: record disability/pregnancy-related spells separately and exclude them from trigger math, with occupational-health input.
- Watch the Monday signal honestly: clustering may mean disengagement or a struggling manager — the fix differs from a health issue. Pair with team-level absenteeism rates to see whether it's one person or a culture.
- Publish the policy: secret triggers destroy trust; stated ones plus discretion hold up in tribunals and morale surveys alike.
Knowing Your Score (Employees)
If your employer uses Bradford, track your own rolling-12-month score with this calculator — knowing you're at 180 before requesting an absence-heavy month is practical self-defence. If a chronic condition drives your spells: disclose it (protection needs awareness), ask for the disability adjustment to triggers in writing, and get GP/occupational-health documentation. A score built on discounted-in-error absences is challengeable — spells data comes from the same records behind your attendance percentage, so reconcile both.
Alternatives and Complements
The absenteeism rate measures volume (days ÷ available days) without frequency weighting; Bradford measures disruption. Mature HR uses both: rate for cost and benchmarking, Bradford for individual pattern-flagging — and neither as an autopilot for discipline. Sickness pay context: UK absences run through SSP/occupational schemes regardless of the score; docking sick pay by Bradford band is a policy choice some employers make for enhanced (not statutory) sick pay.
Frequently Asked Questions
What is the Bradford Factor?
An absence score — spells squared times total days (S² × D) over rolling 12 months — that weights frequent short absences far above single long ones, flagging disruptive patterns.
How is the Bradford Factor calculated?
Count separate absence occasions (S) and total days absent (D): B = S × S × D. Four spells totalling 7 days scores 4 × 4 × 7 = 112.
What is a bad Bradford Factor score?
Common bands: under 50 fine; 51-200 informal chat; 201-449 formal review; 450+ warning territory. Every employer sets its own triggers — check the policy.
Why are spells squared?
To encode disruption: each new occasion causes fresh same-day cover chaos, while one long absence is managed once. Squaring makes frequency dominate duration.
Is the Bradford Factor legal?
Using it is lawful; applying triggers mechanically to disability- or pregnancy-related absence invites Equality Act claims — such absences generally must be discounted or thresholds adjusted.
Does one long sickness ruin the score?
No — that is the design: a single 15-day illness scores just 15, while five 3-day absences score 375.
What counts as one spell?
One continuous absence occasion regardless of length — Friday-plus-Monday around a weekend is usually two spells unless certified as one continuous sickness.
Over what period is it measured?
Almost always a rolling 52 weeks — each new absence recomputes the trailing year, so old spells fall out over time.
Can I lower my Bradford score?
Only time removes spells (rolling window). Practically: convert foreseeable appointments to annual leave where policy allows, and get chronic conditions formally discounted.
Do US companies use the Bradford Factor?
It is primarily a UK/Irish tool; US employers more often use points-based attendance systems — which face their own legal pressure when they penalize protected sick leave.
✓ Formula verified • Last updated: August 20, 2026