Incident Rate TRIR Calculator

Example data table

These sample scenarios show how cases and hours change the rate.

Formula used

The Total Recordable Incident Rate (TRIR) normalizes recordable injuries and illnesses by hours worked.

• TRIR = (Total Recordable Cases × Constant) ÷ Total Hours Worked
• Total Recordable Cases includes all OSHA-recordable incidents in the period.
• Total Hours Worked should match the same reporting period.
• Constant is a standard base value used for reporting.
• DART (optional) = (DART Cases × Constant) ÷ Total Hours Worked

How to use this calculator

1. Select the reporting period label that matches your report.
2. Enter your total recordable cases for that period.
3. Enter total hours worked for the same period.
4. Choose the constant required by your reporting method.
5. Optionally include subcontractor cases and hours if needed.
6. Enable DART to compute a second, more serious rate.
7. Press Calculate to view results above the form.
8. Use CSV or PDF export buttons for documentation.

TRIR in construction: professional guide

1) What TRIR measures

TRIR is a lagging safety indicator that converts recordable injuries and illnesses into a rate that is comparable across projects of different sizes. By using hours worked as the exposure base, you can evaluate performance on a small renovation and a large civil program using the same scale.

2) The constant and why it matters

The most common constant is 200,000, representing 100 full-time workers at 40 hours per week for 50 weeks. Using a consistent constant allows internal benchmarking across time. Some clients request alternative bases; the calculator lets you switch without changing your incident counting method.

3) Reliable input data

Accurate TRIR depends on two datasets: (a) your OSHA-recordable case count and (b) total hours worked in the same period. A practical data check is to reconcile hours to payroll totals. Another check is to keep first-aid cases separate so they do not inflate recordables.

4) Subcontractor inclusion

Many construction owners expect a combined rate when subcontractors work under the controlling contractor’s program. If you include subcontractors, add both their recordable cases and their hours worked. For example, if you have 2 recordables and 120,000 hours, and subcontractors have 1 recordable and 40,000 hours, the combined TRIR uses 3 cases and 160,000 hours.

5) Reading the number

A TRIR of 1.000 means one recordable case per 200,000 hours of exposure. Because construction work is variable, review TRIR with context: project phase, workforce mix, task risk, seasonal conditions, and schedule pressure. A short period with low hours can create a volatile rate.

6) Using DART alongside TRIR

DART focuses on more severe outcomes: days away, restricted duty, or job transfer cases. Tracking TRIR and DART together helps avoid misleading signals. Two recordables with no lost time may keep DART low, while a single serious case can raise DART sharply even if TRIR is stable.

7) Trending and targets

For meaningful trendlines, calculate rates on the same cadence (monthly or quarterly) and use rolling totals. A simple dataset might include: cases, hours, TRIR, DART, and top event types. Pair rate targets with leading actions such as audits, hazard reports, and closeout cycle time.

8) Reporting and audit readiness

Store each calculation with its period label, case log reference, and hour source. Exports help you standardize reports for client portals and internal dashboards. When questions arise, you can show the exact inputs used, demonstrate consistency, and trace corrective actions tied to the period.

FAQs

1) What counts as a recordable case?

A recordable case is an injury or illness that meets your recordkeeping criteria, such as medical treatment beyond first aid, restricted work, job transfer, days away, or certain diagnoses. Use consistent case rules each period.

2) Which hours should I use for TRIR?

Use total hours worked for the same period as your case count. Include overtime hours. If you include subcontractors in your rate, include their hours too, using the same time window.

3) Why does my TRIR jump after one incident?

Low total hours can make the rate volatile. One recordable on 10,000 hours equals 20.000 using a 200,000 constant. Longer periods or rolling totals smooth results and improve comparisons.

4) Should I report separate rates by project?

Yes, if you need project-level management. Many firms track both: a company-wide rate and project-specific rates. Keep the same constant and counting method so comparisons remain valid.

5) What is the difference between TRIR and DART?

TRIR includes all recordable cases. DART includes only cases with days away, restricted duty, or job transfer. DART is often used to focus on severity while TRIR reflects overall recordable frequency.

6) Can I exclude subcontractors from my TRIR?

You can, but align with client requirements and your internal policy. If a contract expects a combined rate, exclude neither their hours nor their cases. If reporting separately, keep clear labels.

7) How do I verify my calculation for an audit?

Keep a copy of the case log, the hours source, and the period definition. Export the calculation, then cross-check: cases, hours, constant, and the computed rate. Document any corrections and re-run the report.