Enter site data
Example dataset
| Month | Hours worked | LTI | LTIR (×200,000) |
|---|---|---|---|
| Jan | 82,500 | 0 | 0.000 |
| Feb | 79,250 | 1 | 2.524 |
| Mar | 86,110 | 0 | 0.000 |
| Apr | 90,500 | 2 | 4.420 |
| May | 88,440 | 1 | 2.261 |
These values are illustrative for training and demonstrations.
Recent calculation log (session)
No logged rows yet. Use “Calculate + Add to Log”.
Formula used
Lost Time Injury Rate (LTIR) measures lost time injuries per standard hours worked. It normalizes performance so teams can compare periods fairly.
- Lost Time Injuries: cases with time away from work.
- Total Hours Worked: hours in the same period and scope.
- Normalization Factor: typically 200,000 or 1,000,000 hours.
How to use this calculator
- Choose the reporting period and enter your project label.
- Enter total hours worked for the same scope and timeframe.
- Enter the number of lost time injury cases in that period.
- Select the normalization factor required by your program.
- Click Calculate LTIR to show results above the form.
- Use CSV or PDF downloads for audits, dashboards, and reports.
LTIR in construction safety reporting
1) What the LTIR rate represents
Lost Time Injury Rate (LTIR) is a lagging indicator that expresses the number of lost time injuries per standardized hours worked. Many construction programs normalize to 200,000 hours, roughly equal to 100 people working 40 hours weekly for 50 weeks. This makes performance comparable across projects, trades, and reporting periods.
2) Data inputs that affect accuracy
The calculator uses two core inputs: lost time injury cases and total hours worked. Hours should be captured consistently for direct employees and contractors based on your client requirement. Misaligned scopes (for example, excluding subcontractor hours but counting their injuries) can inflate LTIR and distort trend reviews.
3) Choosing the normalization factor
Select the factor that matches your reporting standard. A 200,000-hour factor is common for many organizations, while some regions and owners request 1,000,000 hours for low-frequency comparisons. Changing the factor does not change safety performance; it changes how the same data is scaled for reporting.
4) Using LTIR for month-to-month tracking
Monthly LTIR can move sharply on small-hour projects. To reduce noise, review rolling totals (for example, 3-month or 12-month hours and injuries) alongside monthly values. The example table on this page shows how one additional LTI can shift the rate when hours are under 100,000.
5) Benchmarking and contractor management
LTIR is often used in prequalification and contractor scorecards. Compare contractors only when reporting rules are aligned: injury definitions, first aid boundaries, restricted work classification, and hour sources. Pair LTIR with proactive metrics such as inspections completed, critical control verifications, and training completion rates.
6) Communicating results to stakeholders
Present LTIR with context: workforce size, high-risk activities, and corrective actions taken. A clear narrative helps owners and internal leadership understand whether the rate reflects a one-off incident or a systemic risk. Export the result to CSV or PDF for consistent reporting in meetings and audits.
7) Common data quality checks
Before publishing LTIR, verify timesheets, duplicate injury records, and date boundaries. Confirm that hours and injuries share the same cut-off times and organizational scope. A quick reasonableness check is hours per LTI; unusually low values can highlight missing hours or misclassified cases.
8) Turning LTIR into improvement actions
Use LTIR as a trigger for learning. When the rate rises, review incident investigations, identify repeating causal factors, and prioritize controls on the highest-risk work fronts. Set improvement targets tied to leading indicators, and validate changes through field observations and supervisor engagement.
FAQs
1) What counts as a lost time injury?
An LTI is an occupational injury or illness that results in time away from work beyond the shift. Use the definition required by your client and local regulations, and keep it consistent across periods.
2) Why is 200,000 hours used so often?
200,000 hours approximates 100 workers at 40 hours per week for 50 weeks. It is a long-standing normalization that makes rates comparable across projects of different sizes.
3) Can LTIR be calculated with zero injuries?
Yes. If LTI equals zero, LTIR will be 0.000 for the selected factor. Track trends over time to avoid overconfidence on low-hour periods.
4) Should contractor hours be included?
If contractor injuries are included, their hours should be included too. Mixing scope can exaggerate the rate and misrepresent performance. Follow the owner or corporate reporting rule.
5) What if our standard uses 1,000,000 hours?
Select the 1,000,000 factor in the calculator. Your underlying hours and injuries remain the same; only the scaling changes so results match your reporting template.
6) How can I reduce LTIR volatility on small projects?
Use rolling periods such as 3-month or 12-month totals, and pair LTIR with leading indicators. This smooths spikes caused by a single case during low-hour months.
7) Is LTIR the same as TRIR?
No. LTIR counts only lost time injuries, while TRIR typically includes additional recordable cases. They measure different outcomes, so keep them separate in dashboards.