How Many First Aiders Do I Need

You’re standing in a warehouse office, headcount spreadsheet open, and someone asks the question that sounds simple until you actually try to answer it: how many first aiders do I need?

Most people guess. They look at last year’s number, or they copy the factory down the road. Consider this: that’s a mistake. Get it wrong and you’re either wasting money on unused training, or you’re leaving injured staff waiting for help that isn’t there.

The short version is — it depends. But “it depends” isn’t useful on its own. So let’s break down what actually drives that number, and how to work it out without losing your mind.

What Is A First Aider

A first aider is someone in your workplace who’s been trained to give immediate help if someone is injured or falls ill at work. Not a paramedic. Not a nurse. Just a normal employee who knows how to stop bleeding, do CPR, use a defibrillator, and keep a situation from getting worse until the pros arrive.

In practice, they’re the person everyone looks at when something goes wrong. That’s a bigger deal than it sounds.

First Aider vs Appointed Person

Here’s what most people miss — you might not need first aiders at all. That’s someone who looks after the first aid kit, calls ambulances, and keeps records. They don’t need full training. If your risk assessment says the chance of serious injury is low, you might just need an appointed person. They just need a brain and a phone.

But the moment your workplace has real risks — machinery, chemicals, height work, lone workers — you’re into first aider territory.

The Legal Bit Without The Legal Jargon

In the UK, the Health and Safety (First-Aid) Regulations 1981 say you must provide “adequate and appropriate” first aid. No fixed number is written in law. Adequate for your risks. That’s the whole rule. Appropriate for your people. And that’s why everyone’s confused.

Why It Matters

Why does this matter? Because most businesses either overdo it or underdo it, and both cost you.

Underdo it and someone has a cardiac arrest in the canteen with no one trained to use the AED on the wall. That’s not a paperwork problem. That’s a life.

Overdo it and you’ve got six first aiders in a 20-person office where the biggest hazard is a stapler. They’re all pulling wages for refresher courses every three years and covering shifts for each other’s training days. Money down the drain.

Turns out, the HSE (Health and Safety Executive) gives guidance, not rules. Think about it: they suggest ratios based on hazard level and headcount. But those are starting points, not gospel.

And here’s a real-talk observation: inspectors don’t count certificates. Plus, they look at your risk assessment. If you can show you thought about it properly, you’re fine. If you guessed, you’re exposed.

How It Works

So how do you actually work out how many first aiders you need? Here’s the method I’ve seen work in real businesses, not just in theory.

Step 1: Do The Risk Assessment

You can’t skip this. Low hazard places — shops, offices, small cafes — have different needs than construction sites or chemical plants.

Write down what could hurt someone. Still, be honest. In real terms, then rate how likely and how bad. That gives you your baseline hazard level: low, medium, or high.

Step 2: Use The HSE Suggested Ratios As A Skeleton

For low hazard workplaces, the HSE suggests:

• Fewer than 25 employees: at least 1 appointed person
• 25–50 employees: at least 1 first aider (Emergency First Aid at Work)
• 50+ employees: 1 first aider per 100 staff

For higher hazard workplaces:

• Fewer than 5 employees: at least 1 appointed person
• 5–50 employees: at least 1 first aider (First Aid at Work) per 50
• 50+ employees: 1 first aider per 25 staff

That’s the skeleton. Now you put meat on it.

Step 3: Adjust For Reality

This is where most guides stop. They shouldn’t.

Think about:

• **Shift patterns.One first aider on days does nothing for the night crew. ** Asthmatic workforce? - **Disability or health conditions.- **Lone workers.They need training too, or a plan to reach help fast. Think about it: - **Absence. In real terms, ** People get sick, quit, go on holiday. ** Someone in a van 40 miles out? Now, a good rule: add one extra for every 5–6 trained, or just build in 20% slack. ** Two buildings on one site? Don’t put all first aiders in Building A. ** If you run 24/7, you need cover on every shift. - **Layout.Because of that, diabetic staff? But you need spare capacity. More trained people helps.

Step 4: Pick The Right Training Level

There are two main certs in the UK:

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• Emergency First Aid at Work (EFAW) — 1 day, basic
• First Aid at Work (FAW) — 3 days, deeper, includes things like fractures and poisoning

Low hazard = EFAW usually fine. High hazard = FAW needed.

And don’t forget mental health first aiders. Different thing, but worth knowing about if your team deals with trauma or high stress.

Step 5: Write It Down

Your calculation, your reasoning, your names. That's why if it’s in the risk assessment, you’re defensible. If it’s in your head, you’re not.

Common Mistakes

Honestly, this is the part most guides get wrong — they list the ratios and walk off. The mistakes happen after that.

One big one: training everyone and calling it done. Now, certificates expire. Now, i’ve seen sites where 8 of 10 “first aiders” let certs lapse because no one tracked dates. You had cover on paper, none in reality.

Another: ignoring travel time. If your site is 20 minutes from an ambulance, you need more hands, not fewer. Rural sites get this wrong constantly.

And the classic — putting the first aider in HR and forgetting they’re never on the factory floor. Coverage isn’t about who’s trained. It’s about who’s there when it kicks off.

Look, I know it sounds simple — but it’s easy to miss that first aid needs change when you hire, move, or buy new equipment. Do it once and forget it? That’s how people get caught out.

Practical Tips

Here’s what actually works, from people who run this properly:

• Use a spreadsheet with expiry dates. Colour-code it. Review monthly. Sounds boring. Stops lawsuits.
• Train across departments. Don’t cluster in one team. Spread the cover.
• Do a drill. Once a year, fake an incident. See who responds and how fast. You’ll learn more in 10 minutes than in 10 meetings.
• Tell people who the first aiders are. Post names and photos. New starter induction should include “if I bleed, go to Sam.”
• Reassess when things change. New machinery, new site, new shift? Redo the math. Don’t wait for the annual review.
• Keep kits checked. A first aider with an empty kit is just a worried employee. Appointed person should audit kits monthly.

The thing is, you don’t need a consultant. You need 30 minutes and a honest look at your place.

FAQ

How many first aiders do I need for 30 office staff? If it’s low hazard, HSE suggests 1 first aider (EFAW) at 25–50 employees. Add cover for holidays and you’ll likely train 2.

Do small businesses need a first aider? Under 5 low-hazard staff? An appointed person is enough. But many still train one EFAW person anyway — cheap insurance.

**

What if my staff work remotely or from home?And ** The same duty of care applies, but the risk profile shifts. Home workers are usually in low-hazard environments, so an appointed person and access to guidance may suffice. Still, if you have clusters of remote staff in one location — say a co-working space or regional hub — treat that as a satellite site and run the numbers for it separately.

Can a first aider also be the fire marshal? Yes, but think about overlap. If the same two people are always pulled for every emergency, you’ve got a coverage gap the moment they’re both off. Spread responsibilities so one incident doesn’t strip your response capacity.

Is mental health first aid a legal requirement? Not under health and safety law in the same way physical first aid is. But if stress, trauma, or burnout are real features of the job, ignoring it is a poor bet. It’s separate training, not a substitute for the physical side.

Conclusion

Getting first aid cover right isn’t about hitting a magic ratio and moving on. It’s about honest assessment, written records, and keeping pace with how your workplace actually behaves day to day. Even so, train the right people, spread them out, track their certificates like they matter — because they do — and make sure everyone knows who to run to when something goes wrong. Do that, and you’re not just compliant. You’re ready.