No law fixes how many first aiders you need, but HSE suggests minimums. Low-hazard workplaces: an appointed person below 25 staff, one EFAW first aider for 25 to 50, then one FAW first aider per 100. Higher-hazard workplaces: an appointed person below 5, one EFAW or FAW first aider for 5 to 50, then one FAW first aider per 50.
Those figures come from HSE’s guidance on the Health and Safety (First-Aid) Regulations 1981, and they are the starting point for any employer asking “how many first aiders do I need?” They describe how many people should be available at all times people are at work, which is not the same as how many you employ. Once you allow for shifts, holidays and spread-out sites, most employers need more.
This guide explains the HSE table, the difference between an appointed person and a trained first aider, and the factors that push your number up. It ends with a five-step method you can use today.
What does the law require?
Regulation 3 of the Health and Safety (First-Aid) Regulations 1981 requires employers to provide first aid equipment, facilities and people that are “adequate and appropriate in the circumstances”. The law sets the standard and leaves the numbers to you.
HSE’s guidance for employers sets the minimum for any workplace: a suitably stocked first aid kit, an appointed person to take charge of first aid arrangements, and information for all employees about those arrangements. Small, low-hazard workplaces may need nothing more. Everyone else decides through a first aid needs assessment, which uses the same thinking as the 5 steps to risk assessment.
How many first aiders do I need? The HSE suggested numbers
HSE’s guidance document L74, First aid at work, gives suggested minimums in Appendix 3, based on hazard level and headcount. HSE calls them “suggestions only”.
| Hazard level | Employees | Suggested minimum |
|---|---|---|
| Low hazard (offices, shops, libraries) | Fewer than 25 | At least 1 appointed person |
| Low hazard | 25 to 50 | At least 1 EFAW trained first aider |
| Low hazard | More than 50 | At least 1 FAW trained first aider for every 100 employed (or part thereof) |
| Higher hazard (light engineering and assembly, food processing, warehousing, extensive work with dangerous machinery or sharp instruments, construction, chemical manufacture) | Fewer than 5 | At least 1 appointed person |
| Higher hazard | 5 to 50 | At least 1 EFAW or FAW trained first aider, depending on the injuries that may occur |
| Higher hazard | More than 50 | At least 1 FAW trained first aider for every 50 employed (or part thereof) |
Source: HSE L74, First aid at work (third edition, 2024 amendment), Appendix 3.
“Or part thereof” means you round up. Two worked examples:
- An office with 120 staff on site. Low hazard, so one FAW first aider per 100 or part thereof. 120 is one hundred plus part of another, so the suggested minimum is 2 FAW first aiders on duty.
- A warehouse with 120 staff on a shift. Higher hazard, so one FAW first aider per 50 or part thereof. That gives a suggested minimum of 3 on that shift.
Same headcount, different answer. Judge hazard by what people actually do rather than your sector label: an office with a print room, a loading bay and maintenance staff has higher-hazard areas inside it. Your risk assessment and accident records should tell you which applies. L74 is clear on one point: where 25 or more people are employed, even in low-hazard work, at least one trained first aider should be provided.
Appointed person, EFAW or FAW: what is the difference?
An appointed person organises first aid. A first aider gives it.
| Role | What they do | Training |
|---|---|---|
| Appointed person | Takes charge of first aid arrangements, looks after the kit and calls the emergency services | None required, though HSE says an EFAW course may help |
| Emergency First Aid at Work (EFAW) | Gives emergency first aid to someone injured or taken ill at work | One-day course; certificate valid for three years |
| First Aid at Work (FAW) | Everything at EFAW level plus a range of specific injuries and illnesses | Three-day course; certificate valid for three years |
Source: HSE L74 paragraphs 74 and 78 to 80. Course lengths are those KeyOstas delivers.
An appointed person cannot replace a first aider your assessment says you need. L74 lets them stand in only when a first aider is absent for “exceptional, unforeseen and temporary” reasons. Annual leave does not count.
What pushes the number up?
The table is a floor. These are the factors HSE lists in L74, and what each usually means in practice.
Shift work
Cover must exist whenever people are working, and L74 says each shift may need separate arrangements. Run the table against each shift’s own headcount. A night shift of 30 in a warehouse needs its own first aider.
Several buildings or floors
The test is how quickly a first aider can reach a casualty. L74 asks you to consider provision on each floor and in each building of a spread-out site.
Remote sites, lone workers and travellers
Sites far from emergency services may need transport arrangements, a better stocked kit and extra training. For staff who travel or work remotely, L74 suggests considering personal first aid kits, and for lone workers a way to call for help, such as a mobile phone. Our lone worker guide covers the rest.
Holidays and sickness
HSE says provision must cover all times people are at work, including annual leave and other planned absences. If your count says one first aider, training exactly one person guarantees gaps.
Shared sites and visitors
On a multi-occupied site one employer can provide cover for everyone, and HSE strongly recommends a written agreement. The Regulations only cover employees, but HSE also strongly recommends including visitors in your assessment, particularly in shops, schools and entertainment venues.
Do self-employed people need first aid provision?
Yes, for themselves. Regulation 5 requires a self-employed person to provide adequate and appropriate first aid equipment for their own use. HSE says someone doing low-hazard clerical work at home would not be expected to provide anything beyond their normal needs.
Defibrillators and mental health first aid
Neither is a fixed requirement under the First-Aid Regulations, but both belong in a needs assessment.
If you provide an automated external defibrillator (AED), HSE says the Provision and Use of Work Equipment Regulations 1998 apply, so you should give information and written instructions on its use. AED use is part of the FAW and EFAW syllabus, and a half-day AED operator course suits other staff.
For mental health, HSE lists mental health first aiders as one option for supporting colleagues. They sit alongside physical first aiders rather than replacing them. See our mental health first aid courses.
Keeping first aiders qualified
FAW and EFAW certificates last three years. L74 says a first aider whose certificate has expired is no longer considered competent until they requalify. FAW holders can renew on a two-day First Aid at Work requalification before expiry, and HSE strongly recommends an annual refresher in between. Keep a record of every expiry date, because a lapsed certificate quietly drops your cover below the number you think you have.
How to work out your number in five steps
- Decide your hazard level for each area, using your risk assessment and accident history.
- Count the most people at work at the same time, shift by shift and building by building.
- Apply the HSE table to each shift and area, rounding up wherever it says “or part thereof”.
- Add cover for holidays, sickness, lone workers, extra floors and visitors.
- Choose EFAW or FAW for each person, book the training and record the expiry dates.
Write the result down. HSE does not require a written needs assessment, but it is the simplest way to show an inspector or insurer how you reached your number. Then tell staff who the first aiders are and where the first aid kits are, as Regulation 4 requires.
Frequently asked questions
Is it a legal requirement to have a first aider at work?
Every employer must make adequate and appropriate first aid provision. The minimum is a stocked kit, an appointed person and information for staff. HSE says at least one trained first aider should be provided wherever 25 or more people are employed, even in low-hazard work.
How many first aiders do I need for 50 employees?
HSE suggests at least one EFAW trained first aider for 25 to 50 employees in low-hazard work, and at least one EFAW or FAW first aider for 5 to 50 in higher-hazard work. That is the number on duty, so most employers train one more person to cover absence.
How many first aiders do I need for 100 employees?
In low-hazard work HSE suggests one FAW first aider per 100 employed, so one for exactly 100 and two for 101 or more. In higher-hazard work it suggests one per 50, so two for 100. Add cover for shifts and absence.
Do I need a first aider if I have fewer than 5 employees?
Not necessarily. HSE’s suggested minimum below 5 employees in higher-hazard work, and below 25 in low-hazard work, is an appointed person and a stocked first aid kit. Your needs assessment may still favour a trained first aider.
Can an appointed person cover when the first aider is on holiday?
No. HSE says an appointed person can stand in only when a first aider is absent for exceptional, unforeseen and temporary reasons. Annual leave does not count.
How long does a first aid at work certificate last?
Three years from the date the course was completed, for both FAW and EFAW. FAW holders can requalify on a two-day course before expiry.
Where to learn more
- First Aid at Work: three-day FAIB-accredited course for full first aid cover
- Emergency First Aid at Work: one-day course for lower-risk workplaces
- First Aid at Work requalification: two-day renewal for current certificate holders
- AED operator training: half-day defibrillator course
- First aid kit contents: what HSE suggests a workplace kit should hold
- RIDDOR reporting explained: which injuries you must report
Get your first aiders trained
KeyOstas delivers FAIB-accredited First Aid at Work, Emergency First Aid at Work and requalification courses at your premises anywhere in the UK, for up to 12 delegates per course, on dates that suit your shifts.
Send an enquiry or call +44 (0)330 056 9534.