To calculate your OSHA DART rate, multiply your number of DART cases by 200,000, then divide by the total hours your employees actually worked during the year. The result is the number of injuries or illnesses per 100 full-time workers that were serious enough to cause days away from work, restricted duty, or a job transfer. The 200,000 in the formula represents roughly what 100 employees work in a year at 40 hours per week for 50 weeks, which is what lets a small shop and a large plant be compared on the same scale.1Occupational Safety and Health Administration. Figure 2-8 Incidence Rate Worksheet
Written out: (DART cases × 200,000) ÷ total hours worked = DART rate.
A worked example. Say your establishment logged 8 DART cases last year and your workforce clocked a combined 450,000 hours. The math is (8 × 200,000) ÷ 450,000 = 3.56. That means about 3.56 of every 100 full-time workers had an injury or illness serious enough to miss work, take restricted duty, or transfer to another role.
The formula itself is simple. The errors happen in the two numbers you plug into it.
Which Cases Count in the Numerator
A DART case is any recordable work-related injury or illness that results in at least one of three outcomes: the employee misses work, performs restricted duties, or is transferred to a different job. All three trigger the same count. Even if a single incident causes all three, it counts as one DART case.
Recordability comes first. An injury or illness is recordable when it is work-related, is a new case, and meets one of OSHA’s general recording criteria: death, days away, restricted work or transfer, medical treatment beyond first aid, loss of consciousness, or a significant injury or illness diagnosed by a licensed healthcare professional.2eCFR. 29 CFR Part 1904 Subpart C – Recordkeeping Forms and Recording Criteria Cancer, chronic irreversible diseases, fractured or cracked bones, and punctured eardrums are always recordable when diagnosed.3Occupational Safety and Health Administration. General Recording Criteria – 1904.7
Recordable is not the same as DART. A worker who needs stitches but returns to full duty the next day with no restrictions has a recordable case. It raises your Total Case Incident Rate. It does not affect your DART rate. Only cases with days away, restricted work, or a job transfer belong in the DART numerator.
The First-Aid Line
The distinction between first aid and medical treatment decides whether many injuries become recordable at all, which means a misclassification here quietly inflates or deflates your DART rate. OSHA treats first aid as a closed list. If a treatment is not on it, the treatment counts as medical treatment and the case is recordable.3Occupational Safety and Health Administration. General Recording Criteria – 1904.7 First aid includes non-prescription medications at non-prescription strength, cleaning and bandaging surface wounds (but not sutures or staples), tetanus shots (but not other vaccines), hot or cold therapy, elastic wraps and non-rigid supports, drilling a nail to relieve pressure, draining a blister, removing a splinter, eye patches and finger guards, simple massage, and fluids for heat stress. Prescription-strength medication, rigid immobilization, sutures, physical therapy, and chiropractic treatment all cross into medical treatment.
Temporary and Staffing Agency Workers
When a staffing agency supplies workers, the employer who provides day-to-day supervision records the injuries and counts the hours. That is almost always the host employer, because the host controls the hazards and directs the work.4Occupational Safety and Health Administration. Temporary Worker Initiative – Injury and Illness Recordkeeping Requirements Include their hours in your denominator and their DART cases in your numerator. Only one employer records the case; make sure it is not being logged twice.
Which Hours Count in the Denominator
Total hours worked means actual hours on the job, for every employee you supervise: full-time, part-time, seasonal, and temporary. Leave out vacation, sick leave, holidays, and other paid time off. Those hours were not worked. For salaried employees whose actual hours you do not track, you can estimate from scheduled hours, but the estimate should reflect reality rather than a flat 2,000-hour assumption that ignores overtime and absences.
Inflating the denominator by including paid-but-not-worked time drops your DART rate artificially. OSHA’s Site-Specific Targeting program randomly inspects establishments with suspiciously low DART rates precisely to catch this.5Occupational Safety and Health Administration. CPL 02-01-067 Site-Specific Targeting
Counting Days for Each Case
Once a case is a DART case, the day count on the OSHA 300 Log has its own rules.
Counting starts the calendar day after the injury or the onset of illness. The day of the incident itself is never counted.3Occupational Safety and Health Administration. General Recording Criteria – 1904.7
Restricted work applies when the employee cannot perform one or more routine job functions, or cannot work the full workday they were scheduled to work, because of the injury or illness. The restriction can be imposed by you or by a licensed healthcare professional.6Occupational Safety and Health Administration. If an Employee Who Routinely Works Ten Hours a Day Is Restricted A transfer is any move to a different job than the regular assignment, temporary or permanent.
Count calendar days, not workdays. Weekends and holidays inside a period of absence or restriction all count. An employee hurt Wednesday who is out Thursday through the following Monday is five days away, not two.
The count caps at 180 calendar days per case. Once you hit 180, enter 180 on the log and stop.3Occupational Safety and Health Administration. General Recording Criteria – 1904.7
DART Rate Versus Total Case Incident Rate
The DART rate and the Total Case Incident Rate (TCIR, sometimes TRIR) share the same formula but count different cases. TCIR includes every recordable injury and illness. DART includes only those that produced days away, restricted duty, or a transfer. Your DART rate will almost always be lower than your TCIR because it filters out cases where the employee got medical treatment but returned to full, unrestricted work.
TCIR tells you how often injuries happen. DART tells you how often injuries are serious enough to disrupt normal work. Clients, insurers, and general contractors often ask for both, so calculate them side by side from the same Form 300A totals.
What a Good DART Rate Looks Like
Your rate means nothing without a comparison. A 2.0 might be strong in nursing home care and weak in accounting. The Bureau of Labor Statistics publishes national average incidence rates every year by industry through its Survey of Occupational Injuries and Illnesses. For 2024, the overall private-sector DART rate was 1.4 per 100 full-time workers. Construction was 1.3. Manufacturing and healthcare each averaged 1.7.7U.S. Bureau of Labor Statistics. Incidence Rates of Nonfatal Occupational Injuries and Illnesses by Industry and Case Types
To find your comparison, look up your six-digit NAICS code. If you don’t know it, search by keyword on the Census Bureau’s NAICS site, or contact your nearest OSHA office.8Occupational Safety and Health Administration. How Do I Determine the Correct NAICS Code for My Company Then match your rate to your industry group in BLS Table 1.
Why the Number Matters
OSHA Inspection Targeting
OSHA’s Site-Specific Targeting program pulls DART data from the electronic reporting system to build inspection lists. It flags establishments with elevated DART rates, establishments whose rates are climbing over multiple years, and establishments that failed to submit their data at all. Rates that sit at or above twice the national average and keep rising land squarely on the inspection radar.5Occupational Safety and Health Administration. CPL 02-01-067 Site-Specific Targeting
Contractor Prequalification
Large companies and government agencies routinely ask bidders for their DART rate and TCIR. In oil and gas, construction, and manufacturing, prequalification questionnaires often set a hard DART threshold. A rate above the industry average can knock you out of consideration no matter what your price looks like.
Insurance and Workers’ Compensation
A consistently high DART rate tells insurers your workplace produces more serious injuries than your peers. That pushes up experience modification rates and workers’ compensation premiums. A sustained downward trend gives you leverage at renewal.
Getting the Inputs Right
The DART rate is only as accurate as the data behind it. The inputs live on Form 300A, the annual summary of work-related injuries and illnesses, which is compiled from the running Form 300 Log and the individual Form 301 incident reports. Records are kept per establishment (each physical location), not per company, so a business with three warehouses calculates three DART rates.9Occupational Safety and Health Administration. 1904.46 – Definitions
Employers with 10 or fewer employees during the previous calendar year, and employers in certain lower-hazard industries listed by NAICS code, are partially exempt from routine recordkeeping.10Occupational Safety and Health Administration. 1904.1 – Partial Exemption for Employers With 10 or Fewer Employees11Occupational Safety and Health Administration. 1904 Subpart B App A – Partially Exempt Industries If that describes you, you may not need to calculate a DART rate for OSHA at all, though you may still need one for contract bids or insurance.
If you already have logs and you find a case you didn’t initially record was actually recordable, or a first-aid case that later turned into days away or restricted work, update the log and the summary. Records must be kept and kept accurate for five years after the calendar year they cover.12Occupational Safety and Health Administration. 1904.33 – Retention and Updating An artificially low DART rate produced by underreporting is the fastest way to invite the inspection that finds it.