Incidence Rate Calculator
Formula Reference
Incidence Rate = (Number of Cases × Multiplier) ÷ Total Hours Worked| Injury / combined categories | 200,000 base — rate per 100 full-time workers |
| Illness-only subcategories | 20,000,000 base — rate per 10,000 full-time workers |
Where to Find Your Case Counts (OSHA Form 300A)
| Total Recordable | Column H + Column I + Column J |
| DAFW | Column H |
| Restricted/Transfer | Column I |
| Other Recordable | Column J |
| Illness subcategories | Columns M-1 through M-6 |
Methodology, interpretation & sources
Purpose. The general-purpose BLS (Bureau of Labor Statistics) incidence rate formula — the same underlying calculation used for TRIR, DART, and DAFW rates, applicable to any case category on your OSHA Form 300A.
How to use the result. Start with source data you can verify, enter values on a consistent unit and time basis, and record the assumptions used. The main inputs on this page include Case Category Sets the correct standardization multiplier automatically — illness-only subcategories use a different base than injury/combined categories., Custom Multiplier, Number of Cases, Total Hours Worked, Your Name, Email. Re-run the calculation when those assumptions change rather than carrying an old result forward.
Decision use. Use this calculator to standardize a safety-performance indicator from your own verified incident and exposure data. Consistent definitions are essential when comparing sites or time periods.
Limitations. Confirm that the numerator event definition and denominator exposure-hours basis match the reporting framework used by your organization or regulator.
Primary references. Use the current edition/version that applies to your jurisdiction and organization:
Editorial note. Prepared and maintained by Impact Tech Solutions. Editorially updated 28 September 2026. No individual professional credential is claimed on this page; high-consequence, statutory, tax, engineering or health decisions should be independently verified against the current primary source and, where required, a qualified professional.