Sick days are the one wellbeing number every board sees. They’re also the cheapest line on the bill.
Ask most organisations how their people are doing and they’ll reach for the absence rate. It’s tidy, it’s monthly and it fits on a slide. It’s also the least useful number in the building.
What the numbers say.
There are 2 big sources, and they disagree.
The ONS says UK workers lost 148.8 million days to sickness in 2025: 2.0% of working hours, or 4.4 days each. That rate was unchanged on the year before.
Employers paint a darker picture. The CIPD’s 2025 survey of over 1,000 organisations puts absence at 9.4 days per employee, a record high, up from 7.8 in 2023. Mental ill health is now the top cause of long-term absence.
Different methods, different samples. Both agree the trend is up. Neither tells you much about the people still at their desks.
The smallest line on the bill.
Deloitte puts the annual cost of poor mental health to UK employers at £50.6bn. Divide that by the UK’s 30.2 million payrolled employees and you get £1,676 a head:
Presenteeism: £788
Turnover: £646
Absence: £242
Absence, the part everyone measures, is about a seventh of the total. The 2 biggest costs are people working below capacity and people leaving. Neither shows up in an absence report until it’s too late.
3 things absence data can’t see.
Presenteeism. The colleague who logs on with a migraine counts as present. So does the one who has been quietly burning out since spring.
Leaveism. People who use holiday to be ill never appear in sickness figures. The CIPD found nearly two thirds of organisations have seen it.
The run-up. Long-term absence rarely arrives out of nowhere. By the time someone is signed off with stress, there have usually been months of working through it first. Absence is a lagging indicator. It tells you what already happened.
There’s a cautionary tale here. When the Health and Safety Executive investigated the University of Birmingham, it emerged the university had concluded stress wasn’t a significant issue, based partly on its sickness absence rates and how often staff used the employee assistance programme. The HSE disagreed, and issued a formal Notice of Contravention in December 2025. The numbers looked fine. The staff were not.
A note of fairness: low absence can be good news. The CIPD found that over a third of employers with home workers saw absence fall, and checked whether presenteeism had simply taken its place. It hadn’t. The point is to know which story your own numbers are telling.
What to watch instead.
Absence still belongs on the dashboard. It just shouldn’t be alone there. Alongside it:
Leave patterns. Unused allowance, single days booked at short notice.
Out-of-hours activity. Email and messaging volume in evenings and at weekends.
Stress signals. 46% of UK workers told Gallup they felt a lot of stress the previous day. Do you know your own figure?
Return to work. 27% of people coming back from stress-related absence got no support at all (Mental Health UK, 2026). How does yours go?
Managers’ state. The people holding everyone else together are often the most depleted. Their state sets the room’s.
None of these are perfect. Together they show you the bill before it arrives.
This is part of a series on what dysregulation really costs. Start with presenteeism.
The Working Well assessment shows you where your organisation sits and what dysregulation is likely costing you. Your Working Well briefing, with the full cost model, follows by email.
Take the Working Well assessment today. workerbe.co.uk/working-well
Sources
ONS, Sickness absence in the UK labour market, May 2026; payrolled employees, Sept 2026
CIPD/Simplyhealth, Health and wellbeing at work, 2023 and 2025
Deloitte UK, Mental health and employers, May 2024; per-employee figures derived by Worker Be
Times Higher Education, 18 December 2025; Clyde & Co, January 2026 (HSE and the University of Birmingham)
