How the Bradford Factor formula works
The Bradford Factor is a human resources metric used across UK workplaces to measure employee absenteeism. It is based on the operational principle that frequent, short-term, unplanned absences are far more disruptive to team productivity and staffing schedules than occasional longer-term illnesses.
The mathematical formula calculates the Bradford score as B = S² x D, where S represents the total number of separate spells (occasions) of absence over a rolling 52-week period, and D represents the total cumulative working days lost to sickness absence during that same period.
Because the number of absence instances is squared, taking multiple single days off generates a dramatically higher score than taking the same total number of days in one continuous period.
Most UK organisations map Bradford scores into standardized trigger tiers based on CIPD absence management guidelines: Tier 1 (0 to 49 points) indicates normal attendance requiring no action; Tier 2 (50 to 124 points) prompts an informal line manager check-in; Tier 3 (125 to 399 points) triggers a first written warning; Tier 4 (400 to 649 points) initiates a final written warning; and Tier 5 (650+ points) leads to formal capability review and potential dismissal consideration.
Worked example: Comparing single vs repeated absences
Suppose an employee takes 6 total days of sickness absence during a rolling 52-week period across 3 separate spells of 2 days each, with 260 contracted working days per year.
Under the Bradford Factor formula, their score is calculated as 3² x 6 = 9 x 6 = 54 points.
Their annual absence rate is 2.3% of contracted working time, with an average absence length of 2.0 days per spell.
If all 6 days had occurred within 1 single continuous spell, the equivalent single-absence score would equal only 6 points (1² x 6 = 6). Splitting the time off into 3 separate occasions creates a 9.0x disruption impact multiplier.
A score of 54 points falls into Tier 2 (Low threshold), which typically prompts an informal return-to-work discussion with a line manager rather than formal disciplinary action.
Inputs for the Bradford factor calculator
Number of absence instances (spells)
The total number of separate sickness absence occasions or spells taken over the rolling 52-week evaluation period.
Total days absent
The cumulative number of contracted working days missed across all sickness absence spells during the same 52-week period.
Contracted working days per year
Your contracted working days per year, typically 260 days for a standard full-time employee working 5 days per week.
CALCULATOR QUESTIONS
Bradford factor calculator questions
What is a good Bradford Factor score?
A Bradford Factor score under 50 is generally considered acceptable and reflects normal attendance with no management intervention required. Scores between 50 and 124 represent low concern, while scores of 125 and above usually trigger formal HR attendance procedures.
Can an employer dismiss you based solely on your Bradford Factor?
No. Under UK employment law, the Bradford Factor is merely an alerting mechanism, not an automated disciplinary sanction. Employers must investigate the underlying medical reasons, conduct fair return-to-work interviews, consider occupational health advice, and explore reasonable adjustments before taking formal dismissal action.
Does disability-related absence count towards the Bradford Factor?
Under the Equality Act 2010, employers must make reasonable adjustments for employees with disabilities. Employers typically adjust Bradford Factor trigger thresholds upwards or discount disability-related sickness spells entirely to prevent unlawful discrimination.
What is the rolling 52-week reference period?
The Bradford Factor is measured across a rolling 52-week (1-year) window. As calendar days advance, older absence instances drop off your active total exactly 52 weeks after they occurred, lowering your current score.