The short answer: poor mental health costs UK employers around £51 billion a year. Most of that is not sick days. Nearly half comes from people who are at work but struggling, and much of the rest comes from absence and from people leaving. For a single organisation, one long mental health absence or one burnt out leaver can easily cost more than a year of training.
When I sit down with business owners and HR managers, the question I hear most is some version of “can we justify spending money on this?” It is a fair question. But it is usually asked the wrong way round. The money is already being spent. It just isn’t labelled as mental health.
This article is part of our practical guide to workplace mental health training for UK employers.
How much does poor mental health cost UK employers?
The most widely quoted figure comes from Deloitte. In 2024 it estimated that poor mental health costs UK employers around £51 billion a year. Of that, about £24 billion comes from presenteeism: people who come to work while unwell and cannot perform at their usual level.
The Health and Safety Executive’s latest figures show how big the problem has become:
| Measure (Great Britain, 2024/25) | Figure |
|---|---|
| Workers with stress, depression or anxiety caused or made worse by work | 964,000 |
| Working days lost to it | 22.1 million |
| Average days lost per case | 22.9 |
| Share of all work-related ill health | 52% |
| Share of all working days lost to work-related ill health | 62% |
The CIPD’s 2025 Health and Wellbeing at Work report found that sickness absence has reached 9.4 days per employee a year, up from 5.8 days before the pandemic. Mental ill health was the most common cause of long-term absence, cited by 41% of organisations.
Put simply: mental health is now the biggest single reason people are off work for any length of time.
Where does the money actually go?
National figures are useful, but they can feel a long way from your own business. So here is where the cost turns up inside an organisation.
1. Absence. This is the one people notice. Salary for someone who isn’t there, overtime or agency cover, work that slips. Mental health absences also tend to be long. The average case costs nearly 23 working days, according to the HSE. Our own estimate, based on average UK pay and typical time off, puts a single mental health related absence at around £4,000.
2. Presenteeism. This is the biggest cost and the hardest to see. Someone is at their desk, on the shop floor or behind the wheel, but they are exhausted, distracted or anxious. Mistakes creep in. Decisions take longer. Colleagues pick up the slack. It never shows up on a report, which is exactly why it gets ignored.
3. People leaving. When someone burns out and leaves, you lose their knowledge and pay to replace them. Oxford Economics estimated the cost of replacing one employee at around £30,614, once you count recruitment and the months it takes a new starter to get up to speed. I call this the invisible cost, because it almost never gets recorded as a mental health cost.
4. Management time. Managers spend hours on absence meetings, return to work conversations, covering rotas and dealing with the knock-on effect in the team. Without training, those conversations often take longer and go less well.
5. Risk. When a mental health condition meets the Equality Act definition of disability and reasonable adjustments are not made, a tribunal claim can follow, and compensation for discrimination is uncapped. You can read more in Mental Health at Work: What the Law Actually Requires of You.
How to work out what it costs your organisation
You do not need a finance team to get a rough figure. Start with the two costs you can count:
- Number of mental health related absences last year, multiplied by £4,000
- Number of people who left because of stress, burnout or mental health, multiplied by £30,614
Add the two together. Then remember that presenteeism, the biggest cost nationally, is not in that number at all.
A worked example. A 60 person business has two people off with stress last year and loses one experienced team leader to burnout. That is roughly £8,000 plus £30,614: over £38,000, before counting a single hour of lost productivity. For comparison, a full group of 16 people on an accredited Level 1 course starts from £995.
If you would rather not do the sums yourself, our free risk score tool asks seven quick questions and gives you a costed estimate in under two minutes.
What actually brings the cost down?
Deloitte’s research found that employers get back, on average, around £4.70 for every £1 spent on supporting employee mental health. That is an average across many kinds of support, not a promise, but it points in one clear direction: acting early is cheaper than acting late.
In my experience, the things that make the biggest difference are:
- Managers who can have the conversation. Most problems get expensive because nobody said anything until it reached crisis point. See How to Talk About Mental Health at Work: A Manager’s Guide.
- Trained people spread across the organisation, not just in HR, so changes get noticed sooner. Read How Many Mental Health First Aiders Does Your Organisation Need?
- Clear routes to support, so a trained person knows exactly where to take someone next.
- Measuring the right things. Track mental health related absence and turnover before and after, not just how many certificates you issued.
If you want a low cost first step, a 90 minute Bitesize Workshop starts from £385 online. If you are not sure your current setup would support trained people, our Workplace Mental Health Systems and Support Review looks at what you already have first.
Frequently asked questions
What is presenteeism?
Presenteeism is when someone comes to work while unwell and cannot perform at their normal level. Deloitte estimates it costs UK employers around £24 billion a year, more than absence.
What is the most common cause of long-term sickness absence in the UK?
Mental ill health. In the CIPD’s 2025 survey, 41% of organisations named it as a top cause of long-term absence.
Is workplace mental health training worth the money?
On average, employers get back around £4.70 for every £1 spent on mental health support, according to Deloitte. Training works best when it is joined up with clear support routes and managers who know how to use it.
The bottom line
You are already paying for poor mental health. The only choice is whether you pay for it late, through absence and people leaving, or early, through people who know what to do when a colleague starts to struggle.
If you want to talk through what would make sense for your organisation, book a free call. No hard sell, just an honest conversation.