Annual Average Employees on OSHA 300A: How to Calculate the Field
Add up the number of employees paid in every pay period during the year, divide by the number of pay periods, and round up to the next whole number.
The short version
Add up the number of employees paid in every pay period during the year, divide by the number of pay periods, and round up to the next whole number. Include full-time, part-time, seasonal, and temporary employees covered by the log.
The annual average employees field looks harmless, but it creates debates between payroll, HR, and safety.
What you need before you start
Gather these first, and keep them with the record afterward:
- The payroll report used for hours worked, with the date it was pulled
- Adjustments: paid leave removed, supervised temporary workers added
- The pay periods and headcounts behind the annual average employees figure
- The rate calculation with the case counts it used
The rule behind the steps
OSHA incidence rates scale case counts to 200,000 hours, which is 100 full-time workers at 40 hours a week for 50 weeks. TRIR (also called TCIR) = total recordable cases (300A columns G + H + I + J) × 200,000 ÷ total hours worked. DART = (cases in columns H + I) × 200,000 ÷ total hours worked. The 300A itself asks for the annual average number of employees and the total hours worked by all employees covered by the log (29 CFR 1904.32(b)(2)). For comparison, the BLS private-industry averages for 2024 were a TRIR of 2.3 and a DART rate of 1.4.
Step by step
- Pull the headcount paid in each pay period.
- Add them up.
- Divide by the number of pay periods.
- Round up to the next whole number.
- Keep the worksheet with the 300A.
Tip: Use a documented method that reflects employees covered by the OSHA 300 Log.
Where this usually goes wrong
Teams sometimes use year-end headcount even when staffing changed materially during the year.
The denominator does as much work as the numerator. One wrong hours figure moves every rate, and the same hours also go on the 300A and into the ITA submission. The fix is to document the method once (which payroll report, which exclusions, which estimates) and use the same hours for the 300A, the ITA, and every rate.
HR usually holds the headcount, leave, and restriction paperwork that recordkeeping depends on, so the handoff to safety matters as much as the rule.
Special situations
- Seasonal businesses should keep the supporting calculation with the certified summary.
- Hours worked means hours actually worked. Vacation, holiday, and sick leave are paid but not worked.
Worked example
A landscaping company has 26 biweekly pay periods. It paid 60 people in each of the 13 spring and summer periods and 25 in each of the other 13: (13 × 60 + 13 × 25) ÷ 26 = 1,105 ÷ 26 = 42.5, which rounds up to 43. Its year-end headcount of 25 would have understated the average by 18.
How it affects the rest of your records
Hours worked and average employees appear on the posted 300A and in the ITA submission, so a figure that is wrong for the rate is also wrong on two regulatory documents.
Where 300log helps
300log totals each establishment's columns as cases are recorded and keeps average employees and hours worked with the 300A, so the rate, the posted summary, and the ITA submission all use the same numbers.
For a quick answer without an account, use the free rate calculator.
Frequently asked questions
What is the formula for TRIR?
TRIR = total recordable cases × 200,000 ÷ total hours worked. The case count is the sum of 300A columns G, H, I, and J.
What counts toward DART?
Cases with days away from work (column H) plus cases with job transfer or restriction (column I). It counts cases, not days.
Is there an official severity rate?
No. OSHA and BLS publish no official severity rate. Some teams track a day count rate, (days away + days restricted) × 200,000 ÷ hours, from an archived OSHA worksheet, but it has no BLS benchmark.
Does hours worked include salaried staff?
Yes, if they are covered by the log. Use actual hours where you have them and a reasonable, documented estimate for exempt staff.
Sources
Primary regulation and agency guidance this article relies on.
- [1]29 CFR 1904.32: Annual summary certification and postingOccupational Safety and Health Administration · osha.gov(opens in a new tab)
- [2]OSHA ITA CSV documentationOccupational Safety and Health Administration · osha.gov(opens in a new tab)
- [3]29 CFR 1904.29: OSHA Forms 300, 300A, and 301Occupational Safety and Health Administration · osha.gov(opens in a new tab)
Written and reviewed by the 300log Editorial Team. Guidance, not legal advice: confirm edge cases with OSHA or counsel.