When someone collapses, cuts a hand open or breathes in fumes, the first few minutes matter a lot. In that time, the person who helps is not a doctor. It is whoever is standing nearby. The question for every employer is simple: have we got enough trained people on site to help?
Enter the number of workers and the hazard level of your workplace below, and the calculator will show the minimum cover you should have.
What is a first aider?
A first aider is a worker who has completed a recognised first aid course and holds a valid certificate. They can give first aid for injuries and sudden illness until medical help arrives, such as treating bleeding, burns, choking, faints and heart emergencies.
There is also a smaller role called an appointed person. This person does not give first aid beyond basic emergency help. Their job is to take charge when something happens, call the ambulance and look after the first aid kit. In small, low-risk workplaces, an appointed person may be enough.
How the calculator works
The calculator follows the guideline set out in UK Health and Safety Executive (HSE) first aid guidance. It looks at two things: the number of employees on site, and whether the work is lower or higher hazard.
Lower hazard workplaces are places like offices and shops.
- Fewer than 25 employees: at least 1 appointed person
- 25 to 50 employees: at least 1 first aider
- More than 50 employees: at least 1 first aider for every 100 employees
Higher hazard workplaces are places like construction sites, factories and chemical plants.
- Fewer than 5 employees: at least 1 appointed person, or a first aider if your assessment says so
- 5 to 50 employees: at least 1 first aider
- More than 50 employees: at least 1 first aider for every 50 employees
The result is a minimum. It is the number to start from, not a target to stop at.
Worked examples
An office with 80 employees (lower hazard). The workplace has more than 50 people, so the rule is 1 first aider per 100. 80 / 100 = 0.8, which rounds up to 1 first aider.
A small shop with 20 employees (lower hazard). With fewer than 25 people, 1 appointed person is the minimum.
A factory with 120 employees (higher hazard). With more than 50 employees, the rule is 1 first aider per 50. 120 / 50 = 2.4, which rounds up to 3 first aiders.
A construction site with 30 workers (higher hazard). The site has between 5 and 50 workers, so 1 first aider is the minimum.
The number is only the start
The calculator counts employees. Real life is messier, and your first aid needs assessment should look at all of this:
- Shifts: if you run a day and a night shift, each shift needs its own cover. A factory with 120 workers split into three shifts of 40 needs a first aider on every shift, not just three people who all work the day shift.
- Leave and sickness: a first aider who is on holiday or off sick cannot help. Train extra people so that cover never drops to zero.
- Several floors or buildings: help should reach an injured person quickly. A first aider on the ground floor is not much use to someone on the fifth floor with no lift.
- Remote or lone workers: people who work alone or far from help may need a trained person with them, or a clear emergency plan.
- Visitors and the public: shops, schools and training centres have people on site who are not employees, and they should be counted in your thinking.
- Past accidents: if your records show frequent injuries of a certain type, train people and stock supplies for those.
- Distance to hospital: if the nearest ambulance or hospital is far away, you need stronger on-site cover.
- Special risks: work with chemicals, heights, heavy machines or electricity may call for specialist training.
What should a first aid kit contain?
The contents depend on the risks of the place, but most kits include:
- A guidance card on basic first aid
- Plasters in different sizes, and sterile dressings
- Bandages and safety pins
- Disposable gloves
- Eye wash, where tap water is not close by
- Foil blankets
- Face shields or resuscitation aids
Check the kit often. A kit with expired or missing items is not a first aid kit. Put someone in charge of checking it each month and after each use.
Step by step
- Count the people on site at the busiest time, including each shift.
- Decide if your workplace is lower or higher hazard.
- Enter the numbers in the calculator and note the minimum.
- Add extra cover for shifts, leave, floors and remote work.
- Train the people and renew certificates before they expire.
- Tell all staff who the first aiders are and how to reach them.
- Review your plan after any accident and when the workforce changes.
Make first aiders easy to find
A trained first aider does no good if no one knows who they are. Put their names and phone numbers on notice boards, and mark first aid boxes with the standard green and white sign. Add the information to induction training for new staff. In an emergency, people should not need to search for help.
Common mistakes
- Counting people on paper but not on each shift
- Having only one first aider, so there is no cover for leave
- Letting certificates run out
- Putting a higher-hazard site on the lower-hazard rule
- Training people but not telling anyone who they are
- Leaving an empty first aid box on the wall
- Forgetting visitors, contractors and customers
Linking it to your wider safety plan
First aid is the last line of defence. It does not prevent harm, it only limits it. Use the risk matrix calculator to find the hazards that most need controls, and check how well your site is performing with the incident rate calculator. Fire is another emergency to plan for, and the fire extinguisher quantity calculator helps with that.
Frequently asked questions
How many first aiders do I need?
It depends on the number of workers and the hazard level. For a lower hazard workplace of 25 to 50 people, the minimum is 1 first aider. For higher hazard workplaces, it rises with every 50 employees.
What is the difference between a first aider and an appointed person?
A first aider has completed a recognised course and can give first aid. An appointed person takes charge in an emergency and looks after the equipment, but is not trained to give first aid in the same way.
Do I need first aiders for every shift?
Yes. Cover must be there whenever people are working.
Is the calculator result a legal requirement?
No. It is a guideline based on UK HSE guidance. Check your local law, your client’s rules and your own needs assessment.
How long does first aid training last?
Certificates usually need to be renewed every few years. Check the period on your certificate and plan refresher training ahead of time.
Learn this properly
First aid at work and emergency planning are covered in NEBOSH, IOSH and OSHA courses. ISH Institutes teaches these in Peshawar. Chat with us on WhatsApp and we will help you pick the right course.