Enter four numbers from your OSHA logs and get your Total Recordable Incident Rate, DART rate, and Lost Time Incident Rate — plus an honest read on what those numbers can and cannot tell you.
Formula: (cases × 200,000) ÷ hours worked. 200,000 hours represents 100 full-time employees working a full year — the OSHA standard basis.
TRIR (Total Recordable Incident Rate) is the number of OSHA-recordable injuries and illnesses per 100 full-time employees per year. It’s calculated as recordable cases multiplied by 200,000, divided by total hours worked. It is the most-quoted safety metric in industry — in customer prequalifications, insurance submissions, and M&A data rooms.
DART (Days Away, Restricted, or Transferred) counts only the recordable cases serious enough to take someone off their normal job. Same formula, narrower numerator. Because it filters out minor recordables, many carriers and sophisticated customers weight DART more heavily than TRIR.
LTIR (Lost Time Incident Rate) narrows further to cases involving days entirely away from work. It’s the bluntest of the three — and the one most correlated with the claims that move your experience modification rate and your workers’ comp costs.
It depends entirely on your industry. A rate that’s excellent in food manufacturing would be alarming in an office. The Bureau of Labor Statistics publishes incidence rates by NAICS code annually — benchmark against your own code at bls.gov/iif, not against a generic number someone quoted you.
The more important caution: a falling TRIR does not mean falling risk of serious injury. The rate counts frequency, not severity — a paper cut and an amputation each count once. Companies routinely drive TRIR down while their serious injury and fatality exposure stays flat. If you run safety by this number alone, you are managing the scoreboard, not the game.
200,000 hours equals 100 employees working 40 hours a week for 50 weeks — a standardized company-year. Using it as the multiplier lets a 30-person shop and a 3,000-person plant compare rates on the same basis.
Work-related injuries and illnesses involving death, days away from work, restricted work or job transfer, medical treatment beyond first aid, or loss of consciousness, plus certain specific conditions. The recordkeeping determinations are genuinely technical — misclassification in both directions is common, and it distorts every rate on this page.
Yes — this is the most important limitation of the metric. TRIR measures how often anything recordable happened, not how bad it could have been. Serious injury and fatality precursors — high-energy near misses — often don’t appear in the recordable count at all.
A rate is a symptom. If your TRIR, DART, or mod is drifting the wrong way, the cause lives in how the operation is designed — and that’s a conversation worth thirty minutes.
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