To calculate your Total Recordable Incident Rate (TRIR), multiply the number of recordable workplace incidents by 200,000, then divide by the total hours all employees worked during the same period. The result tells you how many recordable injuries or illnesses occurred per 100 full-time workers in a year, giving you a standardized number you can track over time and compare against industry averages.
The TRIR Formula
OSHA’s incidence rate formula is straightforward:
(Number of recordable incidents × 200,000) ÷ Total employee hours worked = TRIR
The 200,000 multiplier represents the annual hours that 100 full-time employees would work: 100 workers × 40 hours per week × 50 weeks per year. This standardization is what makes the metric useful. A company with 50 employees and a company with 5,000 employees can be compared on equal footing, because the rate is always expressed per 100 workers.
A Worked Example
Say your company had 7 recordable incidents last year, and your employees worked a combined total of 500,000 hours. Plug those numbers in:
(7 × 200,000) ÷ 500,000 = 2.8
Your TRIR is 2.8, meaning for every 100 full-time employees, you’d expect about 2.8 recordable incidents over the course of a year. To put that in context, the most recent Bureau of Labor Statistics data shows national averages of 2.2 for construction, 2.7 for manufacturing, and 3.4 for healthcare and social assistance. A TRIR of 2.8 would be slightly above average for manufacturing but well below average for healthcare.
What Counts as a Recordable Incident
Getting the formula right is the easy part. The harder question is which incidents belong in the numerator. OSHA requires you to record a work-related injury or illness on your 300 Log if it results in any of the following: death, days away from work, restricted work or job transfer, medical treatment beyond first aid, or loss of consciousness.
The distinction between “first aid” and “medical treatment” is where most of the confusion lives. OSHA maintains a specific, closed list of what qualifies as first aid. If a treatment isn’t on that list, it’s medical treatment, and the case is recordable. First aid includes things like:
- Using non-prescription medications at nonprescription strength
- Cleaning, flushing, or soaking wounds
- Using eye patches or finger guards
- Removing splinters with tweezers or irrigation
- Draining a blister or drilling a nail to relieve pressure
- Administering tetanus shots (but not other immunizations like hepatitis B or rabies vaccines)
- Using temporary splints, slings, or neck collars during transport
- Drinking fluids for heat stress
If a physician recommends a non-prescription medication at prescription strength, that crosses the line into medical treatment and becomes recordable. Physical therapy and chiropractic treatment are also considered medical treatment, not first aid. Visits solely for observation, counseling, or diagnostic procedures like X-rays don’t count as medical treatment on their own.
Getting Your Hours Worked Right
The denominator, total hours worked, needs to capture every hour actually worked by every employee during the period you’re measuring. This includes salaried and hourly workers, full-time and part-time. It does not include paid time off, holidays, sick leave, or other non-working hours. For salaried employees who don’t clock in and out, most companies estimate based on their standard schedule.
If you’re calculating TRIR for a period shorter than a full year, the formula still works the same way. You simply use the recordable incidents and hours from that specific period. The 200,000 multiplier doesn’t change. A quarterly TRIR is perfectly valid, though rates based on smaller windows and fewer hours tend to swing more dramatically from one period to the next.
One common error is forgetting to include hours worked by temporary or contract workers who appear on your payroll or whom you supervise on a day-to-day basis. If you direct their work, their hours and their injuries generally belong in your calculation.
TRIR vs. DART Rate
TRIR captures all recordable incidents, from a case requiring prescription medication all the way up to a fatality. The DART rate (Days Away, Restricted, or Transferred) uses the same formula but narrows the numerator to only those incidents serious enough to cause missed work, restricted duties, or a job transfer. The calculation is identical:
(Number of DART cases × 200,000) ÷ Total employee hours worked = DART rate
Because DART excludes less severe recordable cases (like a worker who received medical treatment but stayed at full duty), it’s always equal to or lower than TRIR. Many companies track both. TRIR gives you the broadest picture of how often people get hurt. DART tells you how often injuries are serious enough to change someone’s work status. A company with a low TRIR but a DART rate nearly as high has a problem: almost every incident it has is a serious one.
OSHA Reporting Requirements
Calculating TRIR isn’t just a best practice. Certain employers are required to submit injury and illness data electronically to OSHA through the Injury Tracking Application. Whether you need to submit depends on your establishment size and industry. Establishments with fewer than 20 employees at peak staffing are exempt regardless of industry. Establishments with 20 to 249 employees only need to submit if their industry is specifically listed in OSHA’s recordkeeping regulation. Establishments with 100 or more employees in designated high-risk industries must submit detailed data from their OSHA 300 and 301 forms.
These thresholds apply per establishment, not per company. A firm with 500 total employees spread across five small locations might have different reporting obligations at each site.
Improving Your TRIR Over Time
Because TRIR is a rate rather than a raw count, the only ways to lower it are to reduce incidents or increase the hours denominator (which, in practice, means growing your workforce without a proportional rise in injuries). For most organizations, the lever that matters is reducing recordable incidents.
Tracking near-misses and first-aid-only cases, even though they don’t appear in your TRIR, gives you a leading indicator. A spike in minor incidents often precedes a rise in recordable ones. Consistent incident classification also matters. If your safety team is uncertain whether a case is first aid or medical treatment, review it against OSHA’s closed list. Misclassifying a recordable case as first aid doesn’t just undercount your rate; it creates compliance risk if OSHA audits your 300 Log.