How to Calculate TRIR & DART from the OSHA 300 Log

Your 300 Log Already Holds the Numbers

Two rates decide how your safety record reads to a general contractor, an insurer, or a prequalification portal (and if that portal is also demanding your raw 300 Logs, read what OSHA actually requires you to hand over first): TRIR (Total Recordable Incident Rate) and DART (Days Away, Restricted, or Transferred). Both come straight off the OSHA 300 log you are already required to keep (29 CFR 1904.29(a)); you just need the right formula and the right columns.

At a glance: TRIR and DART both use the same formula — (cases × 200,000) ÷ total hours worked. The 200,000 is 100 full-time employees working 40 hours a week for 50 weeks, so the rate reads as "recordables per 100 workers per year." TRIR counts every recordable case (columns G+H+I+J); DART counts only cases with days away, restriction, or transfer (columns H+I). To calculate TRIR, multiply your number of OSHA-recordable cases by 200,000 and divide by the total hours worked by all employees during the year; DART uses the same formula but counts only cases with days away, restricted duty, or job transfer.

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The Formula (Straight from OSHA)

OSHA's Recordkeeping Forms Package states it this way:

Total number of injuries and illnesses × 200,000 ÷ Number of hours worked by all employees = Total recordable case rate

The numerator is the cases you recorded under the general recording criteria of 29 CFR 1904.7. The denominator is the same total hours you already enter on Form 300A under 29 CFR 1904.32(b)(2)(ii).

The only thing that changes between rates is which cases you count in the numerator.

On the OSHA 300, column G is deaths, H is cases with days away from work, I is cases with job transfer or restriction, and J is other recordable cases (see 1904.7 for how those outcomes are defined and counted).

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Worked Example

A construction firm employed the equivalent of a mid-size crew and its payroll shows 176,000 total hours worked for the year. Its OSHA 300 log has 6 recordable cases, of which 3 involved days away from work or restricted duty.

TRIR:

TRIR = (6 × 200,000) ÷ 176,000
     = 1,200,000 ÷ 176,000
     = 6.82

DART:

DART = (3 × 200,000) ÷ 176,000
     = 600,000 ÷ 176,000
     = 3.41

So this firm has a TRIR of 6.82 and a DART of 3.41 — 6.82 recordable cases and 3.41 days-away/restricted cases per 100 full-time workers per year. DART is always ≤ TRIR, because DART cases are a subset of recordable cases.

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Where "Total Hours Worked" Comes From

The denominator trips people up more than the numerator. The rule of thumb:

• Use actual hours worked, pulled from payroll: the hours employees were actually on the clock.
• Do not include vacation, holidays, sick leave, or other non-work time, even if employees were paid for it.
• Include overtime hours, which are hours worked.
• Include the workers you supervise day to day, such as temporary help service workers. Their cases go on your log under 29 CFR 1904.31(b)(2), so their hours belong in the denominator.
• Salaried / no time clock: OSHA's 300A worksheet tells you to estimate the hours actually worked when you only keep paid hours or have employees not paid by the hour. Use real timesheet data whenever you have it.

Getting hours wrong skews the rate in both directions — undercount hours and your rate looks worse than reality; overcount and you hide real frequency.

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"But We Have Fewer Than 100 Employees"

A frequent question: if I only have 30 workers, shouldn't I divide 200,000 by 30 instead of using the full number? No. You always use 200,000. That constant is what standardizes every employer onto the same "per 100 full-time workers" scale — changing it would make your rate incomparable to the BLS industry averages and to everyone else's. A small firm simply plugs its actual hours worked into the denominator, and the math scales correctly on its own.

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What Counts as "Good"? Benchmark, Don't Guess

There is no OSHA pass/fail TRIR. A rate is only meaningful against a reference:

1. Your industry. The Bureau of Labor Statistics publishes incidence rates by industry (NAICS code) each year from its Survey of Occupational Injuries and Illnesses. Compare your TRIR/DART to the average for your NAICS — a roofing contractor and an office both live in very different ranges.
2. Your own trend. You keep five years of logs under 29 CFR 1904.33(a); a rate that falls year over year across them is a sign the program is working.
3. The bid context. Some general contractors and prequalification systems set TRIR or EMR thresholds. Know the number you're being measured against before you bid.

A TRIR below your industry average and trending down is the target. A rate of exactly 0 is possible and excellent — but only credible with real hours worked and an honest log behind it.

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TRIR Is Not EMR

They get conflated constantly, so keep them straight:

Both matter for prequalification, but they answer different questions. TRIR asks how often are people getting hurt? EMR asks how much are those injuries costing relative to peers?

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The Most Common Mistakes

• Counting first-aid-only cases. The first-aid list in 29 CFR 1904.7(b)(5)(ii) is not recordable, and those cases must not be in the numerator; over-recording inflates TRIR. (See When Is an Injury Recordable?)
• Using scheduled hours instead of actual hours worked.
• Forgetting overtime in the hours total.
• Changing the 200,000 constant for small headcounts.
• Mixing DART and TRIR columns — DART is H+I only, never J.

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The standard, tools & related reading

• The standard: Recordkeeping — 29 CFR 1904 · general recording criteria (1904.7)
• On the job: Incident Cost Calculator · Safety Pays Calculator · OSHA 300A Auto-Filler
• Related guides: OSHA 300 Log Requirements — Complete Guide · Forms 300, 300A & 301 · When Is an Injury Recordable? · The ROI of Safety

Your incident rate is only as honest as the log behind it — get the recordability calls right first, and the math takes care of itself.