Free tool for UK builders

How many first aiders do I need? First aid needs calculator

Answer a few questions about your site. You will see HSE’s suggested first-aid people and kit for it, with a link to the regulation or guidance behind every line. Your own needs assessment decides what you provide.

How the calculator works

The law does not set a number of first-aiders. The Health and Safety (First-Aid) Regulations 1981 say an employer must provide first-aid equipment, facilities and first-aiders that are adequate and appropriate in the circumstances. You decide what that means with a first-aid needs assessment.

HSE’s guidance on the Regulations, L74 First aid at work (third edition, amended in 2024), has a chart of suggested numbers in its Appendix 3. HSE says the numbers in that chart “are suggestions only”. The chart lists construction as an example of higher-hazard work, so this calculator always uses its higher-hazard column:

Fewer than 5 employees: “At least 1 appointed person”
5 to 50 employees: “At least 1 EFAW or FAW trained first-aider, depending on the type of injuries that may occur”
More than 50 employees: “At least 1 FAW trained first-aider for every 50 employed (or part thereof)”

The other questions add what L74 says about remote sites, shifts, lone and travelling workers, and shared sites. For the full picture, read our guide to first aid on a construction site.

Every outcome the calculator can show

These are all the lines the calculator can show, so you can check them against your own site. Follow the links for the full wording of each source.

First-aid people, by number of workers

First-aid people: at least 1 appointed person

For higher-hazard work with fewer than 5 employees, HSE's suggested starting point is: "At least 1 appointed person". (L74 Appendix 3)
The appointed person takes charge of the first-aid arrangements, including looking after the equipment and facilities and calling the emergency services when required. HSE says an appointed person should be available to do this at all times when people are at work. (L74 para 78)
An appointed person does not need first-aid training, though HSE says they may benefit from an emergency first aid at work (EFAW) course. (L74 para 80)
There is still the possibility of an accident or sudden illness, so HSE says you may wish to provide qualified first-aiders instead of an appointed person. (L74 para 80)
The law allows an appointed person instead of a first-aider only where the nature of the work, the number of employees and the location of the workplace make that adequate and appropriate. (reg 3(4))

First-aid people: at least 1 trained first-aider

For higher-hazard work with 5 to 50 employees, HSE's suggested starting point is: "At least 1 EFAW or FAW trained first-aider, depending on the type of injuries that may occur". (L74 Appendix 3)
EFAW training covers emergency first aid to someone who is injured or becomes ill at work. FAW training includes EFAW and also covers a range of specific injuries and illnesses, such as injuries to bones, muscles and joints, burns and scalds, eye injuries and major illness. (L74 para 5 and Appendices 5 and 6)
HSE does not choose between EFAW and FAW for you. Look at the injuries your work could cause, and choose the level of training that covers them. (L74 Appendix 3)

First-aid people: FAW trained first-aiders

For higher-hazard work with more than 50 employees, HSE's suggested starting point is: "At least 1 FAW trained first-aider for every 50 employed (or part thereof)". For example, 51 to 100 workers means at least 2. (L74 Appendix 3)
HSE says a first-aid room will usually be necessary on large construction sites. It should be easy to reach with a stretcher, clearly signposted, and a designated person should be responsible for it. (L74 paras 47 and 48)

For every employer

Training and cover

A first-aider must have had appropriate training and hold appropriate qualifications. (reg 3(2))
HSE no longer approves first-aid training providers, so check that the provider you choose is competent. (HSE: what employers need to do)
Plan cover for holidays and sickness. Annual leave does not count as an exceptional absence: if your assessment says you need first-aiders, one should be available whenever the need arises. (L74 para 81)
HSE lists construction, and working in remote areas, as examples where extra training in haemostatic dressings, wound packing and tourniquets for life-threatening bleeding may be relevant. (L74 Appendix 4, Table 3)

First-aid kit

Provide at least one suitably stocked first-aid container for each work site, marked with a white cross on a green background. Large sites may need more than one. (L74 paras 36 and 37)
There is no mandatory list of contents. HSE gives a suggested minimum for low-hazard work and points to British Standard BS 8599. Whatever kit you use, its contents should reflect your needs assessment. (L74 Appendix 2)
Keep containers easy to reach, near hand washing where possible and protected from dust and damp. Check them often and restock soon after use. (L74 paras 37 and 38)
If mains tap water is not readily available for washing wounds and eyes, provide at least one litre of sterile water or sterile saline in sealed, disposable containers. (L74 para 40)
Your needs assessment may show you need extra items, for example foil blankets, haemostatic dressings, tourniquets, or shears that can cut through clothing. (L74 para 39)

Telling everyone

Tell your employees about the first-aid arrangements, including where the equipment, facilities and first-aid people are. (reg 4)
Put up at least one first-aid notice in a prominent place on each site, and include first aid in the site induction. (L74 para 83)
On a construction site, where necessary, arrangements must be made for dealing with any foreseeable emergency, and everyone they cover must be familiar with them. Include first aid in those arrangements. (CDM 2015 reg 30(1) and (3))

Writing it down

You do not have to write your needs assessment down, but HSE says keeping a record helps you show an inspector how you decided on your first-aid provision. L74 Appendix 1 is a record form you can use. (L74 para 9 and Appendix 1)

If you are self-employed and work on your own

Self-employed and working on your own

Work on a construction site is a prescribed undertaking, so as a self-employed person there you must provide, or make sure there is provided, the equipment you need to give first aid to yourself while at work. (reg 5 and SI 2015/1583 Schedule para 3)
Where you work on premises controlled by an employer, or alongside other self-employed people, each of you is responsible for your own first-aid provision. You can agree joint arrangements with the others. (L74 para 85)
If you take on an employee, even for one job, the employer duties apply. Run this calculator again as an employer. (reg 3)

Your first-aid kit

There is no mandatory list of contents. HSE gives a suggested list for a travelling first-aid kit. Stock yours for the injuries your work could cause. (L74 Appendix 2)
If mains tap water is not readily available for washing wounds and eyes, provide at least one litre of sterile water or sterile saline in sealed, disposable containers. (L74 para 40)

Depending on your site

Because the site is remote

Make arrangements so that suitable transport is available to get a casualty to medical help. (L74 para 24)
Check that the first-aid kit is adequate in case the emergency services are delayed. (L74 para 24)
Tell the emergency services, in writing, where the site is and about any particular circumstances, including specific hazards. (L74 para 24)
For people working in remote areas, consider special arrangements such as personal communicators and extra training. (L74 para 21)

Because people work shifts or out of hours

First-aid provision must be available whenever employees are at work. You may need separate arrangements for each shift. (L74 para 22)
HSE's suggested numbers are for the people available at all times people are at work, so apply them to each shift. (L74 Appendix 3)

Because people work alone or travel

Decide whether workers who travel, or move between sites, should carry a personal first-aid kit. (L74 para 21)
Make sure anyone working alone has a way to call for help in an emergency, such as a mobile phone. (L74 para 21)

Because other firms share the site

On a shared site, one employer can take responsibility for first-aid cover for all the workers. Share information about the hazards so the shared cover is adequate. (L74 para 25)
All employers should agree the arrangements, and workers should be told about them. HSE strongly recommends a written agreement between the employers. (L74 para 25)

Put it in your paperwork

Brief it at the site induction

Tell everyone who the first-aider or appointed person is and where the kit is. Our free site induction template has a section for it.

Free site induction template →

Add it to the RAMS

Record the first-aid arrangements and the nearest A&E in the emergency section of the job’s RAMS.

Free RAMS generator →

More free tools: all free tools and templates.

Sources

The Health and Safety (First-Aid) Regulations 1981, regulation 3 (duty of employer to make provision for first-aid) — legislation.gov.uk · Accessed 31 October 2026
The Health and Safety (First-Aid) Regulations 1981, regulation 4 (duty of employer to inform employees of the arrangements) — legislation.gov.uk · Accessed 31 October 2026
The Health and Safety (First-Aid) Regulations 1981, regulation 5 (duty of relevant self-employed person to provide first-aid equipment) — legislation.gov.uk · Accessed 31 October 2026
The Health and Safety at Work etc. Act 1974 (General Duties of Self-Employed Persons) (Prescribed Undertakings) Regulations 2015, Schedule paragraph 3 (construction) — legislation.gov.uk · Accessed 31 October 2026
L74 First aid at work: Guidance on regulations (third edition 2013, reissued with amendments 2015, 2018 and 2024) — Health and Safety Executive · Accessed 31 October 2026
First aid at work: what employers need to do — Health and Safety Executive · Accessed 31 October 2026
First aid at work: frequently asked questions — Health and Safety Executive · Accessed 31 October 2026
The Construction (Design and Management) Regulations 2015, regulation 30 (emergency procedures) — legislation.gov.uk · Accessed 31 October 2026
The Health and Safety (First-Aid) Regulations (Northern Ireland) 1982 — legislation.gov.uk · Accessed 31 October 2026