How this instrument works
DART rate takes the count of OSHA-recordable injuries serious enough to cause days away from work, job restriction, or a transfer, and divides it by the hours actually worked, then rescales the result by 200,000. That constant is not arbitrary: it is exactly the annual hours logged by 100 full-time employees, so the formula answers one question — how many DART cases would this workforce produce if it were sized at exactly 100 workers for exactly one year.
Safety directors, workers' compensation underwriters, and general contractors reviewing a subcontractor's bid all read this figure the same way: as a size-independent injury measure they can set against a Bureau of Labor Statistics benchmark for the same industry code, or against a client's own prequalification cutoff. A 30-person machine shop and a 3,000-person distribution network can be ranked on one scale precisely because raw case counts never get compared to each other directly.
The result says nothing about severity beyond the DART or non-DART line, and nothing about near misses, first-aid-only treatment, or cases still open at year end. It also depends entirely on how carefully hours worked was logged — payroll estimates and OSHA-log hours frequently disagree, and a site that pads or under-reports its hours will quietly distort the outcome in either direction without a single injury changing.
- Enter the count in DART cases (days away, restricted, or transferred) — every OSHA-recordable case from the period involving lost time, restricted duty, or a transfer.
- Enter Total hours worked by all employees for the same period, including overtime and part-time hours, excluding paid time off.
- Read DART rate in the output — the figure annualized and normalized to 100 full-time workers.
- Compare the result against a Bureau of Labor Statistics industry average or a client's prequalification threshold.
- Adjust either field to see how a shift in case count or hours worked moves the rate instantly.
Worked example — 6 cases, 500,000 hours
A distribution center's OSHA 300 log shows 6 DART cases for the year — recordable injuries with days away, restricted duty, or a transfer — against 500,000 hours worked by the full workforce across every shift. Multiplying 6 by 200,000 gives 1,200,000; dividing that by 500,000 hours worked gives a rate of 2.4.
That 2.4 sits inside the range the Bureau of Labor Statistics publishes for many warehousing and manufacturing codes, which is the comparison the constant exists to enable: dividing by hours worked rather than headcount lets this 500,000-hour year sit on the same 100-worker, one-year scale as a much smaller site's 100,000-hour year, so the two figures mean the same thing side by side.
Questions
What counts as a DART case?
A DART case is any OSHA-recordable injury or illness where the employee had days away from work, was placed on job restriction, or was transferred to a different job because of it. A recordable case needing only medical treatment beyond first aid, with no lost time, restriction, or transfer, still counts toward the broader total recordable count, just not this narrower one.
How is DART rate different from TRIR?
TRIR counts every OSHA-recordable case, including ones treated with nothing more than stitches or a prescription-strength ointment. DART counts only the subset serious enough to keep someone away from work, restrict their duties, or move them to another job — so DART is always equal to or lower than TRIR for the same period, and a site can hold a flat TRIR while its DART climbs if injuries are turning more disabling.
Why is 200,000 the constant in the formula?
It stands for one year of work by 100 full-time employees: 100 workers times 40 hours a week times 50 weeks. Multiplying by 200,000 and dividing by actual hours worked rescales any site's raw case count onto that shared 100-employee, one-year basis, which is what lets a 30-person shop and a 3,000-person plant be judged on the same footing.
Should hours worked include overtime and part-time staff?
Yes — hours worked means every hour logged by every employee at the site, including overtime, part-time, and temporary staff, and excludes only hours not worked, such as vacation, sick leave, or holidays. Using payroll headcount times a standard workweek instead of real logged hours is the most common way this figure ends up wrong.
What is a good DART rate?
There is no universal target — it depends on the industry code, since a warehouse and an office carry very different baseline injury exposure. Safety teams compare their own figure against the Bureau of Labor Statistics average for their NAICS code and against the site's own history year over year; a downward trend against a stable headcount is the more meaningful signal than the number alone.
Where do the DART cases come from?
They come from the OSHA 300 log an employer is already required to keep, tallying every recordable case marked with a days-away, job-transfer, or restriction outcome for the year. The annual summary, OSHA Form 300A, is where the case count and hours worked behind this formula are meant to be pulled from before they get posted every February.
References
- OSHA — Injury and Illness Recordkeeping and Reporting
- U.S. Bureau of Labor Statistics — Injuries, Illnesses, and Fatalities
Read this first: This instrument shows arithmetic, not advice. Real offers add fees, taxes and terms that vary by lender and place — verify the figures against your actual paperwork before deciding anything.