Bradford Factor Calculator
Enter the number of separate absence spells and the days absent for each spell group in the last 52 weeks. The calculator works out the Bradford Factor score (S x S x D), shows which management-action band it falls in, breaks down the arithmetic step by step, and plots how the score changes as absences accumulate.
Formula
Worked example
An employee has 3 separate one-day absences and 1 five-day absence. Total spells S = 4 (3 + 1), total days D = 8 (3 x 1 + 1 x 5). Bradford Factor = 4 x 4 x 8 = 128. That falls in the moderate band. If those 8 days had been one continuous absence, the score would be 1 x 1 x 8 = 8 - far lower.
What is the Bradford Factor?
The Bradford Factor is an absence-management metric developed at Bradford University School of Management in the early 1980s. It measures the disruptive impact of employee absence by weighting short, frequent absences more heavily than a single long absence of the same total days. Unplanned one-day absences are harder to cover and cost more in immediate disruption than a planned two-week absence, and the formula reflects that. The score is almost always calculated over a rolling 52-week period, so it resets gradually as older absences drop out of the window.
How the Bradford Factor formula works
The formula is B = S x S x D, where S is the number of separate absence spells and D is the total days absent in the period. Because S is squared, the score rises very steeply with each additional spell. One absence of 10 days scores 1 x 1 x 10 = 10. Two absences totalling 10 days scores 2 x 2 x 10 = 40. Five absences totalling 10 days scores 5 x 5 x 10 = 250. Ten absences totalling 10 days scores 10 x 10 x 10 = 1000. The arithmetic demonstrates why managers often describe the Bradford Factor as a measure of attendance reliability rather than just sickness volume.
How to use this calculator
Enter absence data as groups: a group is a set of spells that all lasted the same number of days. For example, if an employee had three single-day absences and one four-day absence, enter group 1 as 3 spells of 1 day each, and group 2 as 1 spell of 4 days. You can add up to six groups to capture a whole year of mixed patterns. The calculator totals the spells and days across all groups, applies the S x S x D formula, and shows you the resulting score, the appropriate band, and the step-by-step working. The chart compares how your employee's score grows against a single-spell baseline, making it easy to see the penalty for frequent short absences.
Interpreting the score and fair application
Score bands vary between organisations, but broadly: below 50 is considered low and acceptable, 51 to 200 warrants an informal conversation, 201 to 500 typically triggers a formal review, and scores above 500 may justify a final warning or capability process. Always apply the Bradford Factor as part of a wider absence policy, not as a standalone trigger. It cannot account for disabilities, chronic illness, surgery recovery, or pregnancy-related absence, all of which may require a distinct approach under employment law. The score should inform a conversation, not replace one.
Bradford Factor score bands and typical HR actions
| Score band | Level | Typical HR response |
|---|---|---|
| 0 - 50 | Low | No formal action required |
| 51 - 200 | Moderate | Informal discussion, supportive review |
| 201 - 500 | High | Formal review, written warning possible |
| 501 - 900 | Very high | Final warning, consider capability process |
| 900+ | Critical | Dismissal may be considered (subject to legal advice) |
Thresholds vary by organisation. The bands below reflect common practice; always apply them alongside your absence policy.
Frequently asked questions
What is the Bradford Factor formula?
B = S x S x D, where S is the total number of separate absence spells and D is the total number of days absent over the rolling 52-week period. The spell count is squared, which means frequent short absences produce a much higher score than rare long ones of equal total days.
Why does the formula square the number of spells?
Short, unplanned absences are generally more disruptive than a single planned absence of the same length: cover is harder to arrange at short notice and the cumulative interruption is greater. Squaring S gives a larger weighting to an employee who is absent ten times for one day each than to one who is absent once for ten days, even though the total days are identical.
What Bradford Factor score triggers disciplinary action?
There is no single universal threshold - organisations set their own triggers in their absence policy. Common practice is: below 50 no action; 51 to 200 informal discussion; 201 to 500 formal review or written warning; above 500 final warning or capability review. Some organisations also use 900 or above as a threshold at which dismissal may be considered, subject to HR and legal advice.
Does the Bradford Factor reset each year?
It is calculated over a rolling 52-week window, so it does not reset on a fixed calendar date. Absences drop out of the calculation as they become more than 52 weeks old, and the score changes automatically as new absences are added and old ones expire.
Should disability-related absence be included in the Bradford Factor?
In most jurisdictions disability-related absence should be excluded or handled separately. Including it in a Bradford Factor score without adjustment can expose an organisation to disability discrimination claims. Best practice is to discount absences that are directly linked to a known disability or long-term condition and to review those absences under a separate reasonable-adjustments framework.
Is a Bradford Factor of 100 high?
A score of 100 falls in the moderate band (51 to 200). It typically arises from four spells totalling about six days (4 x 4 x 6 = 96) or a similar combination. Most organisations regard this as worth a supportive conversation but not yet a formal disciplinary matter.
How do I calculate the Bradford Factor for multiple absence types?
Group absences by spell length, then add up the total spells and total days across all groups before applying the formula. For example, three single-day absences plus two three-day absences gives S = 5 and D = (3 x 1) + (2 x 3) = 9, so B = 5 x 5 x 9 = 225. This calculator does the grouping automatically when you fill in the optional absence-group fields.