How much mental health cover does your organisation need? Ratios, rotas and cost
Mental health first aid cover exists only while someone trained is at work and can be reached. This guide sizes it from your sites, shifts and absences, then shows the cost in cohorts and days out of the business.
When deciding how many mental health first aiders you need, MHFA England’s current guide for employers asks you to consider your organisation’s structure and the demands on your workforce. It says that for a multisite organisation it is important one is always available at each location. So the number comes from your own sites, shifts, absences and the demands of the work. This guide shows how to work it out. MHFA England, Implementing MHFAiders: Guide for employers, 2024 edition
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The rest of the guide covers what MHFA England and HSE say about numbers and where the figures of one for every 50 or 100 come from, then a seven-step method for sizing cover: drawing the grid of sites, shifts and working days, putting in the names who normally work each slot, finding the slots with one trained name or none, giving people a choice, planning for leavers and the three-year certificate, saying what happens outside working hours and turning the gaps into cohorts and days out of the business. One-off, you won’t need to do this again on this device.
What the guidance says about numbers, and what it leaves to you
The figures that circulate match HSE’s suggestions for physical first aid. Whatever number you start from, your rota decides whether it covers every shift.
What MHFA England and HSE say
MHFA England’s current guide suggests that “for some organisations it may be worthwhile aiming to have as many MHFAiders as physical first aiders”. An option, not a rule: it also notes that the law does not require employers to have mental health first aiders. HSE names mental health trained first aiders among several options for managing mental ill health and says of first aid generally that it “cannot tell you what provision you should make” and there are “no hard and fast rules on exact numbers”. Its L74 guidance was reissued in 2024 to emphasise that employers take account of mental health in their first-aid needs assessment.
Where one for every 50 or 100 comes from
The figures of one for every 50 or 100 employees that circulate for mental health first aid match HSE’s suggested numbers for physical first aiders in its leaflet INDG214: one for every 100 employed in lower-hazard workplaces such as offices, one for every 50 in higher-hazard ones, once more than 50 people are employed. HSE calls them “suggestions only”, says shift work or sites with several buildings may need more and that provision must increase to cover absences. Even the physical numbers came with the rota attached.
A headcount ratio cannot see a night shift, a second site or a fortnight’s leave, so you can meet one and still leave whole shifts uncovered. The method below is ours, built on HSE’s needs-assessment logic: a grid of your working time sets the floor, and demand and choice decide how far above it you go.
Sizing your mental health first aid cover in seven steps
Before you start, gather your sites, the shift patterns at each and your trained people with their certificate dates.
Draw the grid: every site, shift and working day
Put your sites across the top, with remote and hybrid staff as a column of their own, and shifts and working days down the side. Each cell is a stretch of working time in which someone may be struggling. The first-aid needs assessment HSE describes already considers work patterns and how the workforce is distributed; drawing that as a grid for mental health cover is our method.
- Include the shifts nobody in HR works: early starts, nights and weekends. Give overlapping shifts a row each; the late shift cannot use a first aider who went home at 2pm.
- A site too small to train its own still needs a name in its column: someone elsewhere on the same hours, reachable by phone or video.
Put in the names normally working each slot
Fill each cell with the trained people who normally work it. In-date certificates only. Part-timers on their working days only. MHFA England’s guide asks hybrid and remote first aiders to be easily contactable and to say when they will not be available, so count them only in the cells where both hold. Leave out anyone on long-term absence or working their notice.
- Take names from the rota: a first aider counts only in the cells they actually work.
- No certificate dates on file? Ask each first aider now; step 5 needs them.
Find the slots with one name or none
An empty cell is no cover, and a cell with one name is empty on every working day that person is away. The legal minimum for almost all workers is 5.6 weeks’ paid holiday a year, 28 days on a five-day week, and employers can count bank holidays within it. Even at a site that shuts on every bank holiday, that leaves roughly four working weeks a year with the slot empty before sickness, training or a resignation: our arithmetic on the legal minimum. HSE already expects cover for physical first aiders’ annual leave; carrying that over to mental health cover is our step.
- Check the leave calendar too. Two names off in the same fortnight means an empty slot for that fortnight.
- Mark the empty cells apart from the one-name cells: they come first in step 7.
Our rule, not MHFA England’s or HSE’s, and a minimum rather than a target. A small single-site office on one day shift, with two or three in-date first aiders who stagger their leave, may already be there.
Give people a choice of who to talk to
This is where mental health cover stops behaving like physical first aid. Nobody much minds who puts on a plaster, but whether someone speaks up at all can depend on who is on offer. MHFA England’s guide makes the point for location: a first aider at each site for the people there, and for those who would rather contact one outside their own office. Our rule on top: nobody’s only option should be their own line manager or immediate team.
- Where both names in a slot sit in the same team, add a third from another team or list first aiders at other sites as a second route.
- Publish each first aider’s site and usual hours, so people can pick someone they do not work alongside.
- Weigh demand before anyone is trained: a slot with many people in it, or more pressured work, needs more than two names. Once first aiders are in post, add names where they are busiest.
Plan for leavers, movers and the three-year certificate
MHFA England says the training is valid for three years and recommends a refresher every three years to renew it; its employer guide asks you to review when people leave and more training is needed to maintain numbers. Record each first aider’s site, shift and certificate date; HSE already asks employers to record physical first aiders’ certification dates so further training is arranged in time.
- Re-run the grid whenever a first aider leaves, changes site or shift or starts long-term leave, and once a year against certificate dates.
- Predict leavers from how many of your own first aiders left or moved in the last two years, not a borrowed buffer.
Say what happens outside working hours
The grid stops where working hours stop, and so does the role. MHFA England’s guide says first aiders should be contactable in work hours only, without giving out personal contact details, and that staff should be told so. A mental health first aider is never an on-call service, and no rota should make them one. Publish instead the routes that stay open when nobody trained is working.
- Put the routes beside the names, with your employee assistance programme’s out-of-hours line first if you have one, as MHFA England’s guide advises.
- Agree with your first aiders what they do if a colleague reaches them out of hours anyway. The answer starts with the same routes.
Samaritans on 116 123, free, any time day or night; the Samaritans Welsh Language Line on 0808 164 0123, every day from 7pm to 11pm; NHS 111, choosing the mental health option; 999 or A and E if a life is at risk.
Turn the gaps into cohorts and days out
Now the grid gives you a number: the people needed to bring every slot up to the floor, plus any names step 4 added and the leavers step 5 predicts for the coming year. Divide by 16 and round up for cohorts of up to 16, and allow two days out of the business per person for the two-day course. First aiders nearing three years renew with a refresher, not the full course, so plan them separately.
- Count people, not cells. A first aider on the day shift at one site, Monday to Friday, fills five cells, so from the people who apply for the role, choose those whose patterns cover the thinnest slots.
- The two course days come out of the new first aiders’ own shifts, so choose dates with the rota in front of you.
- Several sites can share one cohort online; onsite delivery at each site can mean more, smaller cohorts.
Head office works weekday days; a warehouse runs an early and a late shift on the same days. Three slots a day, so a floor of six names if everyone works all five days. Head office has two in-date first aiders, the early shift one and the late shift none: three more people, one early and two late. That is one cohort and six days out of the business, before leavers or extra names for demand and choice.
Mental Health First Aid for the gaps your grid turns up
We deliver Mental Health First Aid over two days, onsite or online, with up to 16 people in a cohort, accredited by MHFA England, with a conversation about your organisation before delivery. Send us the slots with one name or none and we will come back with a rough quote.
Enquire about Mental Health First AidThis guide is general information for employers and people leaders, not legal or HR advice. Mental health first aiders are not an emergency service and do not replace professional care. The grid, the two-name floor and the cohort arithmetic are our method, not a standard set by MHFA England or HSE. MHFA England’s position is from Implementing MHFAiders: Guide for employers (2024 edition) and its FAQs on how long training is valid. HSE’s position is from First aid at work: Are you an employer?, L74, First aid at work: Guidance on Regulations (reissued with amendments in 2024) and INDG214, First aid at work: your questions answered (2014), whose suggested numbers are for physical first aid. Holiday entitlement is from GOV.UK and applies in Great Britain. Crisis routes: Samaritans and the NHS guide to urgent help for mental health. Related reading: our post on what keeps trained mental health first aiders active after the course.