Accident Frequency Rate (AFR) Calculator

The formula to calculate AFR is:

Number of accidents in financial year / Hours worked in financial year x [Base Hours]

Where Base Hours can be:

• 1,000,000 hours (most common)
• 200,000 hours (OSHA style)
• 100,000 hours (alternative)

Example:

In 2022, a manufacturing company experienced 6 accidents. The company has a workforce of 750 employees. During 2022, total hours worked by all employees was 1,500,000 hours.

To calculate the company's AFR (using 1,000,000 hours):

• Number of accidents: 6
• Total hours worked (for all company employees) during the year: 1,500,000 hours

Use the Formula:

$\text{AFR} = \left( \frac{\text{Number of accidents}}{\text{Total hours worked}} \right) \times 1,000,000$

$\text{AFR} = \left( \frac{6}{1,500,000} \right) \times 1,000,000 = 4.0$

So, the AFR for the manufacturing company in 2022 is 4.0 per million hours worked.

In summary:

• Number of accidents during the year: 6
• Hours worked during the year: 1,500,000
• AFR = 4.0

• LTIFR (Lost Time Injury Frequency Rate): Measures lost-time injuries per million hours worked. Only includes injuries that result in time away from work.
• TRIR (Total Recordable Incident Rate): Measures all OSHA recordable incidents per 200,000 hours worked. Includes a broader range of incidents including medical treatment cases.
• AFR (Accident Frequency Rate): Measures accidents per specified hours worked (commonly per million hours). Definition of "accident" varies by region and organisation.

How do you calculate accident frequency rate?

Divide the number of accidents in the period by the total hours worked in the same period, then multiply by your base: 100,000 hours for the UK HSE method, 200,000 for OSHA-style reporting, or 1,000,000 for the per-million convention common in Australia.

How is AFR calculated under the HSE method?

The HSE method uses a base of 100,000 hours: AFR = (number of accidents / total hours worked) x 100,000. For example, 3 accidents over 450,000 hours gives an AFR of 0.67.

What constitutes an accident in AFR?

The definition of "accident" varies by organisation and region. It typically includes workplace incidents resulting in injury, illness, or property damage. Check your local regulations for specific definitions.

Which AFR formula should I use?

Use 1,000,000 hours for most international standards, 200,000 hours for OSHA-style calculations, or follow your organisation's specific requirements.

How does AFR differ from incident rates?

AFR counts accidents as your organisation defines them, which can include property damage as well as injury. Injury rates such as LTIFR and TRIR count only specific injury or illness cases. Near misses are not accidents and are usually tracked separately.

What is a good AFR rate?

A good AFR varies significantly by industry. Compare your rate against industry benchmarks and focus on continuous improvement rather than absolute numbers.