How to Calculate TRIR and DART Rates (With Worked Examples)

Total Recordable Incident Rate (TRIR) and Days Away, Restricted, or Transferred (DART) rate are the two numbers almost everyone uses to judge your safety record. Customers ask for them in prequalification questionnaires. Insurers look at them at renewal. OSHA uses injury rates to decide which workplaces to target. Your own leadership probably reports them every quarter.

The math is simple, but small mistakes in the inputs are common, and a rate means little until you compare it to something. Here's how to calculate both, step by step.

Why everything is based on 200,000 hours

OSHA rates are normalized to 200,000 hours, which is 100 full-time employees working 40 hours a week for 50 weeks a year. Normalizing lets you compare a 40-person shop with a 4,000-person plant. A TRIR of 2.0 means two recordable cases for every 100 full-time workers in a year, whatever the size of your workforce.

The TRIR formula

TRIR = (Number of OSHA recordable cases × 200,000) ÷ Total hours worked

Recordable cases are every case on your OSHA 300 log for the period. Not sure whether a case belongs there? Our post on first aid vs. medical treatment covers the most common judgment call.
Total hours worked should be actual hours worked by all employees, including overtime, from payroll or timekeeping. Don't include vacation, sick leave, holidays, or other paid time off. Count temporary workers you supervise day to day, since they go on your log too.

Example: A distribution center with 180 employees logged 372,000 hours last year and had 9 recordable cases.

TRIR = (9 × 200,000) ÷ 372,000 = 4.84

The DART formula

DART = (Number of DART cases × 200,000) ÷ Total hours worked

A DART case is a recordable case that involved days away from work, restricted work, or a job transfer. On the OSHA 300 log, that's every case with a checkmark in column H or column I. DART cases are a subset of recordables, so your DART rate can never be higher than your TRIR.

Example: Of that facility's 9 recordables, 5 involved days away or restricted duty.

DART = (5 × 200,000) ÷ 372,000 = 2.69

A third rate worth tracking: DAFW

Some customers and insurers also ask for the Days Away From Work (DAFW) rate, sometimes called the lost-time rate. It uses the same formula but counts only cases with days away (column H). Restricted-duty cases don't count. In the example above, if 3 of the 5 DART cases involved days away:

DAFW = (3 × 200,000) ÷ 372,000 = 1.61

Common mistakes that skew your rates

Using headcount × 2,000 instead of actual hours. It's a fine estimate when you don't have payroll data, but it's often wrong by 10–20% in operations with heavy overtime or many part-time workers.
Counting paid time off as hours worked. That inflates the denominator and makes your rate look better than it is.
Leaving supervised temp workers off the log. If you direct their daily work, the cases belong on your log, even though the staffing agency employs them.
Recording first aid cases. Over-recording raises TRIR for no reason. Under-recording is the bigger risk, because it's a citation.
Mixing up DART and DAFW. A restricted-duty case counts toward DART but not DAFW.

Is your rate good?

A TRIR of 3.0 could be excellent in one industry and poor in another, so always compare yourself to your own sector. According to the Bureau of Labor Statistics, private industry as a whole reported a TRIR of 2.3 and a DART rate of 1.4 for 2024. Rates vary a lot by sector. Transportation and warehousing has historically run well above the national average, and office-heavy industries run well below it.

To compare your own numbers without doing the math by hand, the free OSHA Incident Rate Calculator calculates TRIR, DART, and DAFW from your case counts and hours, then benchmarks them against BLS data for your industry. You don't need an account.

What the rate doesn't tell you

TRIR and DART are lagging indicators. They measure what has already gone wrong. They're also noisy at small facilities: for a 50-person site, one extra recordable can move TRIR by several points. A single year's rate tells you very little about where your next injury will happen.

That information is in the details behind the rate: which areas, tasks, shifts, and hazards keep appearing in your incidents and near-misses. Infranoto pulls that data into one place and uses AI to find the patterns before they become next year's recordables. If you'd like to see it working on your own data, request a demo.

The takeaway

TRIR = recordables × 200,000 ÷ hours worked. DART uses the same formula with only days-away, restricted, and transfer cases.
Use actual hours worked from payroll, not headcount estimates, and leave out paid time off.
DART can never exceed TRIR, and DAFW can never exceed DART.
Benchmark against your industry, not just the national average.
Rates are lagging. The patterns behind them are what let you prevent the next case.

Calculate and benchmark your numbers with the free Incident Rate Calculator.