What the Bradford factor is and how it is calculated
The Bradford factor is a formula some employers use to measure how disruptive a person's absence pattern is.
The Bradford factor is a formula some employers use to measure how disruptive a person's absence pattern is. The score is S x S x D, where S is the number of separate absence spells in a set period and D is the total days absent in that period. Most employers use a rolling 52 weeks, so each time you look, the window moves forward and older absence drops off. Squaring S is the key step: it makes a run of short absences count for far more than a single long one, because short, unplanned absences are usually harder for a team to cover.
The formula comes from HR practice, not from legislation. Neither GOV.UK nor Acas defines a Bradford factor, and there is no legal rule about what score is too high. It is one way of turning an absence record into a number that can prompt a supportive conversation.
Why 10 one-day absences score far higher than one 10-day absence
The same ten days off can produce very different scores depending on how they are spread.
The same ten days off can produce very different scores depending on how they are spread. Because S is squared, the score grows with the square of the spells and only in a straight line with the days.
| Pattern (10 days in total) | Spells (S) | Days (D) | Score (S x S x D) |
|---|---|---|---|
| One absence of 10 days | 1 | 10 | 10 |
| Two absences of 5 days | 2 | 10 | 40 |
| Three absences (4, 3 and 3 days) | 3 | 10 | 90 |
| Five absences of 2 days | 5 | 10 | 250 |
| Ten absences of 1 day | 10 | 10 | 1,000 |
Example trigger bands (employer policy, not law)
Employers who use the Bradford factor pick their own trigger points.
Employers who use the Bradford factor pick their own trigger points. Acas describes trigger points as set by the employer and set out in an absence policy. The table below is only an illustration of the kind of steps a policy might use. It is not an official scale, and your employer's numbers will differ.
| Example score | Example step |
|---|---|
| 0 to 49 | No review needed |
| 50 to 124 | Informal conversation about attendance and wellbeing |
| 125 to 249 | Formal review meeting, with support and adjustments considered |
| 250 to 399 | Second-stage review |
| 400 and above | Senior review before any further step |
Acas advises that review points should not automatically trigger disciplinary action. Treat a high score as a reason to talk to the person and find out what is going on.
Disability, pregnancy and protected leave
Using a score without thought can be unfair and, in the UK, unlawful.
Using a score without thought can be unfair and, in the UK, unlawful. Under the Equality Act 2010 an employer must make reasonable adjustments for a disabled employee, and Acas gives examples that include not counting some or all disability-related sickness absence towards trigger points, or raising the number of absences that trigger a review. Section 18 of the Act also protects a woman from unfavourable treatment because of her pregnancy or an illness that results from it, and Acas says review points can be adjusted so that absence related to pregnancy does not count. Maternity leave itself should never be scored.
In the US, the Department of Labor says employers may not count FMLA leave under no-fault attendance policies or use it as a negative factor in disciplinary actions. Other countries have their own rules on sick leave and protected leave. Remove or adjust protected absence before you calculate, and take advice if you are unsure.
How this calculator counts spells and days
In quick mode you type the spells and days yourself, so you control what counts.
In quick mode you type the spells and days yourself, so you control what counts. In list mode you enter each spell's start and end dates and the date the window ends. A spell counts when any part of it falls inside the window, and only the days inside the window are added to D. Days are counted as Monday to Friday by default, or as calendar days if you choose that. If your policy counts days differently, type the number of days for that spell in the days box and it is used as given. Enter one row per unbroken spell, so a Friday and the following Monday are one spell, not two.
FAQ
What is the Bradford factor?
The Bradford factor is a score some employers use to spot patterns of short, frequent absence. It is worked out as S x S x D, where S is the number of separate absence spells in a period (usually a rolling 52 weeks) and D is the total number of days absent in that period. It is not a legal test and it is not defined by any government or by Acas. Each employer decides whether to use it and what the scores mean.
How do I calculate a Bradford factor score?
Count the separate spells of absence in the period, square that number, then multiply by the total days absent. Three spells covering 10 days in total score 3 x 3 x 10 = 90. One spell of 10 days scores 1 x 1 x 10 = 10. Ten single days score 10 x 10 x 10 = 1,000. Use the calculator above to do it from a spell count or from a list of dates.
Why do ten one-day absences score far higher than one ten-day absence?
Because the number of spells is squared, every extra spell multiplies the score, while extra days only add to it. The idea behind the formula is that frequent short absences are harder for a team to cover than one planned or long absence. That also means the score is blunt: a person with a long-term condition that causes short, unpredictable absences can reach a high score without doing anything wrong, which is why employers need to apply it carefully.
What is a good or bad Bradford factor score?
There is no official answer. A lower score means fewer or shorter absence spells. Employers choose their own trigger points, such as a score at which a manager has an informal chat and a higher one that starts a formal review. The example bands on this page are an illustration, not a standard. Check your own absence policy for the bands that apply to you.
Is it legal to use the Bradford factor in the UK?
Nothing in UK law bans using a score like this, but employers still have to follow the Equality Act 2010 and act reasonably. Acas says employers should set absence trigger points in a clear policy, should not use review points to automatically start disciplinary action, and should consider reasonable adjustments for disabled employees, for example not counting disability-related absence towards trigger points or raising the number of absences that trigger a review.
Which absences should be left out of the score?
Absence related to a disability, and absence related to pregnancy, should not simply be counted against someone. Acas says employers can adjust review points or decide that absence related to disability or pregnancy will not count towards them. Protected leave such as maternity leave should not be scored at all. In the US, the Department of Labor says FMLA leave cannot be counted under no-fault attendance policies or used as a negative factor in disciplinary actions. Other countries have their own rules, so check local law and your policy.
What period does the Bradford factor cover?
Most employers use a rolling 52 weeks: the score looks back 52 weeks from today, so old absence drops out as time passes. Some use a calendar or financial year, or a 12-month or 26-week window instead. The period is set by the employer's policy. In list mode this calculator lets you pick 52 weeks, 12 months or 26 weeks and the date the window ends.
How do I count a spell that includes a weekend, or a half day?
That is also a policy choice. A common approach is to treat one unbroken run of working days as one spell, so a Friday and the following Monday count as one spell of 2 working days. Half days can be entered as 0.5 in quick mode. In list mode you can choose to count working days (Monday to Friday) or calendar days, and overwrite the days for a spell if your rota or part-time pattern differs.
Sources
5 official sources
- Acas: Absence trigger points (employer-set trigger points; adjust for disability and pregnancy; not automatic disciplinary action)
- Acas: Disability-related absence (reasonable adjustments to trigger points under the Equality Act 2010)
- Equality Act 2010, section 18 (pregnancy and maternity discrimination: work cases)
- US Department of Labor: FMLA protections (FMLA leave and no-fault attendance policies)
- Bradford Factor (Wikipedia) for the S x S x D formula and worked examples. The formula is an HR convention: no government body or Acas defines it, and the example trigger bands on this page are illustrative, not sourced from an official scale.
Legal points checked against Acas, legislation.gov.uk and the US Department of Labor. Last verified: September 2026.