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DART Cases, Worker Hours & Incidence Rate

Calculate days-away, restricted-duty and transfer incidence from case frequency and employee-hour exposure over matching periods.

Formula & worked example
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How to use this calculator

Enter the known values in the units shown. Results update as you type.
Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
Use the worked example to check the method. Reset restores the starting fields.

Use the result with context

Results are estimates for planning and education. Confirm rates, taxes, fees, and legal requirements with the relevant institution or a qualified professional before making a financial decision.

Formula and method

Two DART cases over 200,000 employee hours give a DART rate of 2.

DART rate = case count / employee hours × 200,000

Worked example

Enter these known values and leave the other values blank.

DART cases per selected period: 2 / yrs
Employee hours per selected period: 200000 / yrs

DART incidence rate: 2

Assumptions and limitations

For recorded DART cases, use the combined OSHA Form 300/300A H and I case counts, rather than adding days away or restricted days.
Use case frequency and employee-hour exposure from matching periods. Both selectors default to per year; changing one period annualizes that frequency before division.
The factor 200,000 represents the exposure of 100 full-time-equivalent workers at 2,000 hours each. Zero cases give rate zero; employee-hour exposure must be positive.
The displayed bands preserve the captured boundaries of 1.875 and 4.125. They are illustrative, not universal OSHA compliance thresholds. Compare with the appropriate industry and reporting-year benchmark.
Recorded counts are whole cases. A rate-based reverse calculation may produce a fractional estimated case frequency.
Arithmetic uses 64 significant decimal digits, with separate rounding for displayed values.

Common questions

Do I count injury days or cases?

Count qualifying cases. The number of days absent or restricted is not the numerator in the DART incidence formula.

References

Bookify accepts zero DART case frequency and rate while retaining positive employee-hour exposure and the captured incidence formula.

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