The Bradford Factor explained

What is the Bradford Factor?

The Bradford Factor (sometimes called the Bradford Formula) is a way of measuring the disruption caused by absence, not just its volume. The thinking, attributed to research associated with the Bradford School of Management, is simple: many short, unplanned absences are usually harder to plan around than a single, longer one. So the formula deliberately punishes frequency.

It is a management tool, not a law. There is no statutory score, no legally required trigger, and no obligation to use it at all. Employers who do use it decide their own thresholds and how the score feeds into their absence policy.

The Bradford Factor formula

Because S is squared, adding one more separate absence raises the score far faster than adding one more day to an existing absence. That is the whole point.

How to calculate it, step by step

1. Count the spells (S). Each continuous period off - whether it lasts one day or three weeks - counts as a single spell.
2. Count the days (D). Add up every day of absence across those spells in the last 52 weeks.
3. Apply the formula. Multiply S by S, then by D.

Worked example: same days, very different scores

Each person below was absent for a total of 10 days over the year. Only the pattern differs.

Identical days off, scores ranging from 10 to 1,000. That spread is exactly what the Bradford Factor is designed to surface.

Bradford Factor score chart

Looking up a score you have already been given? Find the number of separate absences down the left and the total days across the top. Anything from 200 upward is shaded, since that is where most published scales start talking about formal action.

Read along a row and the pattern is obvious: adding days climbs slowly, while adding separate absences climbs fast. Work out your own with the Bradford Factor calculator, which handles the exclusions and half days too. And for the mechanics people actually argue about - does the score reset every year, what counts as one spell, weekends, part-timers - see the Bradford Factor rules guide.

What counts as a "high" score?

There is no official threshold - and the published ones disagree with each other far more than most employers realise. These are the thresholds three widely-used UK sources actually publish, checked on 9 August 2026:

A score of 500 is "very high, possibly leading to formal discussions" on one source and still well short of the 900 another sets for dismissal. If a number this consequential varies that much between publishers, it is not a standard - it is each organisation's own policy choice.

Whatever you choose, write it down, publish it, apply it consistently for everyone, and use it to prompt a conversation rather than to trigger automatic discipline. Even the calculator publishing the 45/100/900 scale concedes its figures are "for illustration purposes only" and that it "does not take into account any specific factors such as disability".

Does ACAS publish Bradford Factor trigger points?

No. This is worth stating plainly, because a good deal of published advice implies otherwise. Acas guidance on absence trigger points does not mention the Bradford Factor anywhere, and gives no numeric thresholds at all. What it does say is that employers "should set this out clearly in an absence policy", covering what the review points are, how reaching one is flagged, and that reaching one starts an absence review.

So any specific Bradford number attributed to Acas has come from somewhere else. The choice - and the responsibility for defending it - is yours.

Will day-one sick pay push scores up?

Almost certainly, and this is the most immediate reason to revisit your thresholds. Since 6 April 2026, Statutory Sick Pay has been payable from the first day of absence, with no waiting days and no lower earnings limit (what changed).

Short absences that once went unpaid often went unrecorded with them. Now every one generates a payroll entry, so it gets logged. Because the Bradford formula squares the number of separate absences, better recording of one-day absences inflates scores sharply - without anybody's behaviour changing at all.

When the Bradford Factor is (and isn't) the right tool

It works best as an early-warning signal: a way to notice a pattern of short, frequent absence that might otherwise slip past a busy manager, so you can check in and offer support. It works badly as a blunt instrument for punishment.

Fairness caveats you must not skip

• Disability-related absence. Under the Equality Act 2010, absence linked to a disability may need to be discounted or the threshold adjusted as a reasonable adjustment. Counting it the same as other absence risks discrimination.
• Pregnancy and maternity. Pregnancy-related absence must not count against an employee.
• Presenteeism. A metric that punishes every short absence can push unwell people to come in - spreading illness and hurting wellbeing. Balance it with a supportive culture.
• Context beats the number. A score is a prompt to ask "is everything OK?", not evidence on its own. Always look at the reasons behind the pattern.

If in doubt, take advice - Acas publishes helpful guidance on managing absence fairly.

How CoDash handles the Bradford Factor

CoDash calculates the Bradford Factor automatically on a rolling 52-week window, so you never maintain a spreadsheet of spells and days. The score is visible only to HR and the relevant manager, sensitive sickness reasons stay between the employee and HR, and it sits alongside return-to-work interviews and absence reporting - so it prompts a conversation instead of a knee-jerk. See how it fits into time off and absence, or read our guide to UK statutory annual leave.

Frequently asked questions