First Aid / Emergency Response Staffing Calculator

Estimates a starting-point number of trained First Aiders (or Appointed Persons) needed, based on employee count, hazard level, shift pattern, and site count.

Important context before you use this tool: the commonly-quoted "1 first aider per 50/100 employees" table below originates from the UK HSE's 1981 Approved Code of Practice, which was formally withdrawn in October 2013. Current UK law (Health and Safety (First-Aid) Regulations 1981, guided by HSE document L74) does not prescribe a fixed ratio — it requires employers to carry out their own first aid needs assessment covering hazards, shift patterns, site layout, distance from emergency services, and accident history. This calculator uses the legacy ratios only as a widely-referenced starting-point planning estimate, not as proof of legal compliance. A genuine needs assessment is still required.

Total Employees (per site, per shift) Number of people present at one time who would need first aid cover.

Hazard Level

Number of Concurrent Shifts Each shift running at the same time needs its own cover.

Number of Sites / Separate Buildings Each site/building generally needs its own cover.

Absence / Backup Buffer Multiplier Accounts for holidays, sickness, and training downtime among first aiders. A common rule of thumb is to train roughly 1.25–2× the minimum headcount so cover is maintained when someone is away.

Baseline Needed (per shift/site)

Total Minimum (all shifts/sites)

Recommended Trained Headcount

Legacy Reference Ratios Used (Withdrawn 2013 ACOP — Widely-Cited Starting Point Only)

Low Hazard, < 25 employees	1 Appointed Person (no trained first aider strictly required)
Low Hazard, 25–50	1 First Aider
Low Hazard, > 50	1 First Aider per 100 employees
Higher Hazard, < 5 employees	1 Appointed Person
Higher Hazard, 5–50	1 First Aider
Higher Hazard, > 50	1 additional First Aider per 50 employees

Appointed Person vs. First Aider

An Appointed Person takes charge of first aid arrangements (equipment, calling emergency services) but is not trained to administer first aid itself. A First Aider holds a valid certificate (e.g., FAW or EFAW in the UK) and can actively treat injuries. In the US, OSHA does not specify ratios either — 29 CFR 1910.151 instead requires trained first aid personnel unless a hospital, clinic, or infirmary is "in near proximity" to the workplace, judged case-by-case.

This tool provides a general planning estimate only, based on widely-referenced legacy ratios that no longer carry formal legal status in the UK, and no equivalent formal ratio exists under US OSHA regulations either. It does not replace a documented first aid needs assessment, which must additionally account for lone workers, remote locations, public access, accident history, and distance from emergency medical services. For customized calculators tailored to your organization, please contact Impact Tech Solutions.