DART Rate Calculator

What this DART rate calculator estimates

The Days Away, Restricted, or Transferred rate measures how often recordable workplace injuries or illnesses lead to days away from work, restricted duties, or a job transfer. The result is normalized to 200,000 work hours, which approximates the annual exposure of 100 full-time employees. This makes a small company and a large company easier to compare even when their headcounts differ.

DART is a frequency rate, not a severity-day total. A rate of 2.00 means two qualifying cases per 200,000 hours worked; it does not mean two days were lost. For official recordkeeping definitions, consult the OSHA recordkeeping guidance and the criteria in 29 CFR 1904.7.

How to complete each field

Total DART incidents

Enter the number of cases during the reporting year that involved at least one day away, restricted work activity, or transfer to another job. This is required and should be a whole, nonnegative count. Higher incident counts increase the rate in direct proportion. Do not enter the number of lost days, and do not include every recordable case automatically: a recordable case belongs in DART only when it meets a DART outcome criterion.

Total workforce exposure

Enter the actual hours worked by all covered employees during the same reporting period. This is required and must be greater than zero for a rate to exist. Include regular and overtime hours actually worked. Exclude paid vacation, sick leave, holidays not worked, and other non-worked time. More exposure hours reduce the rate when the incident count is unchanged. A common error is combining annual incidents with monthly hours, which overstates the result.

Exposure unit and conversion assumptions

The default unit is total hours. Workdays, workweeks, and FTE-years are convenience inputs that convert back to hours before the formula runs. Changing the unit converts the current value, so the calculated result should remain stable through a unit round trip. The advanced assumptions define hours per workday, hours per workweek, and hours per FTE-year. Use values that reflect your organization’s schedule. These fields are required only when their corresponding unit is selected; zero or negative conversion factors are invalid.

How the calculation works

DART rate = qualifying DART incidents × 200,000 ÷ total hours worked

The calculator first converts the exposure entry into hours. It then multiplies the qualifying case count by 200,000 and divides by those hours. Full precision is retained internally, while the displayed rate is rounded to two decimals. When exposure is blank or zero, the calculator shows an empty state rather than dividing by zero.

The U.S. Bureau of Labor Statistics publishes occupational injury and illness data that can support more meaningful peer comparisons. Use the BLS Injuries, Illnesses, and Fatalities program rather than treating one universal threshold as appropriate for every industry.

How to interpret every result

DART rate and benchmark band

The primary result is the number of qualifying cases per 200,000 hours. This tool labels rates up to 1.875 as low, above 1.875 through 4.125 as moderate, and above 4.125 as high. Those bands provide a simple orientation, not a regulatory safe-harbor or an industry-adjusted target. A zero rate means no qualifying cases were entered for the exposure period. A high rate can result from more cases, fewer hours, or both.

FTE equivalent exposure

This result divides total exposure hours by the selected hours-per-FTE-year assumption. It estimates the worker-year exposure represented by the data and helps catch obvious scale errors. For example, 400,000 hours at 2,000 hours per FTE-year equals 200 FTE-years. It is not a headcount estimate when staff work part time, overtime, or incomplete years.

Cases per one million hours and distance to the next band

Cases per one million hours expresses the same frequency on a larger base and equals five times the DART rate. Distance to the next band shows how far the current rate is from the next higher reference cutoff. In the high band, the calculator instead reports how far the rate is above 4.125. These metrics are descriptive; they should not replace case investigation or corrective-action tracking.

Chart and detail table

The benchmark chart places the current rate beside the two reference cutoffs. The legend and calculation table use the same model values, so their numbers should agree exactly after display rounding. The table also shows converted exposure hours, the 200,000-hour normalization constant, and the formula numerator. Use the Excel export to preserve the current assumptions and results for internal review.

Practical use, tradeoffs, and common mistakes

• Keep the incident count and exposure hours on the same reporting-period basis.
• Apply consistent inclusion rules across facilities and years; changing definitions can create an artificial trend.
• Do not infer safety culture from the rate alone. Small workforces can experience large rate swings from one additional case.
• Compare with an industry and establishment-size benchmark where possible, then investigate the actual cases behind the number.
• Check that contractors, temporary workers, and multi-establishment records are handled consistently with your recordkeeping obligations.

OSHA explains how incidence rates are normalized and used in injury and illness data in its incidence-rate training material. This calculator is an educational analysis tool and does not provide legal or compliance advice.