← Back to the TRIR & DART rate calculator
TRIR (Total Recordable Incident Rate) is recordable cases times 200,000, divided by total hours worked. It answers one question: at this rate of recordable cases, how many would you expect per 100 full-time workers in a year? The rest of this page works through the formula on a real case count, not a rounded example.
TRIR = (recordable cases × 200,000) ÷ total hours worked
DART rate = (DART cases × 200,000) ÷ total hours worked
200,000 is OSHA's own base rate: 100 full-time employees, 40 hours a week, 50 weeks a year. It is fixed regardless of your company's actual headcount, which is what makes the rate comparable between a 12-person crew and a 400-person one.
A contractor logs 6 OSHA-recordable cases over a year in which its employees worked 120,000 hours combined. 2 of those 6 cases involved days away, restricted duty, or a transfer (DART cases); the other 4 needed only medical treatment beyond first aid.
| Figure | Arithmetic | Result |
|---|---|---|
| TRIR | 6 × 200,000 ÷ 120,000 | 10.00 |
| DART rate | 2 × 200,000 ÷ 120,000 | 3.33 |
| Recordable, not DART | 6 − 2 | 4 |
Against a 3.0 target — a common GC prequalification ceiling — this contractor's TRIR of 10.00 is 7.00 points above target.
Holding the recordable count at 6 and adding no new case, the rate falls as more injury-free hours are worked:
solve 6 × 200,000 ÷ target = hours needed for a target of 3.0, and subtract the
120,000 already worked. That is 400,000 − 120,000 = 280,000 additional injury-free hours
— a real number a safety program can plan around, not a guess at how the rate might trend.
The TRIR & DART rate calculator runs this same arithmetic on your own recordable count, DART count, and hours worked, lets you set whatever target rate a bid form or renewal is measuring you against, and converts the injury-free-hours figure into months if you give it your average monthly hours. Nothing you type leaves your browser.
TRIR = (number of OSHA-recordable cases × 200,000) ÷ total hours worked by all employees. 200,000 is OSHA's own base rate: the hours 100 full-time employees work in a year at 40 hours a week for 50 weeks, so the rate reads as recordable cases per 100 full-time workers per year regardless of a company's actual headcount.
OSHA's recordkeeping rule (29 CFR 1904.7) defines it: a work-related injury or illness that results in death, days away from work, restricted work or transfer, medical treatment beyond first aid, loss of consciousness, or a significant diagnosed condition. Deciding whether a specific case meets that bar is the employer's own recordkeeping judgment call — this page and the calculator it links to start from a count you've already made, not from a case description.
Your own OSHA 300 Log of Work-Related Injuries and Illnesses, which every covered employer already keeps, and the OSHA 300A Summary posted every February. Total hours worked is the sum of hours actually worked by every employee in the period, including overtime, and excluding vacation, sick, and holiday time not actually worked.