Calculator Inputs
Use the main fields for an annual or period rate. Add monthly figures to plot the safety trend over time.
Example Data Table
This example uses a 200,000-hour basis for a manufacturing safety review.
| Month | Hours Worked | Lost Time Injuries | Monthly LTIR |
|---|---|---|---|
| Jan | 40,000 | 0 | 0.00 |
| Feb | 42,000 | 1 | 4.76 |
| Mar | 45,000 | 1 | 4.44 |
| Total / Period | 127,000 | 2 | 3.15 |
Formula Used
LTIR = (Lost Time Injuries × Base Hours) ÷ Total Hours Worked
Severity Rate = (Days Lost × Base Hours) ÷ Total Hours Worked
Recordable Rate = (Recordable Injuries × Base Hours) ÷ Total Hours Worked
Average Lost Days per LTI = Days Lost ÷ Lost Time Injuries
LTIs per 100 Workers = (Lost Time Injuries ÷ Employees Exposed) × 100
Most organizations use 200,000 hours for standard benchmarking, but this calculator also supports 1,000,000 hours and custom exposure bases.
How to Use This Calculator
- Select your preferred rate basis: 200,000 hours, 1,000,000 hours, or a custom value.
- Enter the count of lost time injuries for the reporting period.
- Add total hours worked for all relevant manufacturing employees or contractors.
- Optionally enter employees exposed, days lost, recordable injuries, near misses, and a target LTIR.
- Enter monthly hours and monthly LTIs to create a trend graph.
- Click Calculate LTIR to display results above the form.
- Use the CSV and PDF buttons to export the results and monthly trend table.
FAQs
1. What does LTIR measure?
LTIR measures how often injuries lead to time away from work after adjusting for hours worked. It helps compare safety performance across teams, plants, and reporting periods fairly.
2. Why is 200,000 hours commonly used?
A 200,000-hour base roughly represents 100 full-time employees working one year. Many safety programs use it to normalize injury frequency and support consistent benchmarking.
3. When should I use a 1,000,000-hour basis?
Use one million hours when your organization reports enterprise-wide exposure or prefers broader scaling. It is also useful when rates are very low and you want easier comparison across larger operations.
4. What hours should be included?
Include all relevant exposure hours worked during the period, such as regular time, overtime, and contractor hours if they are part of your reporting scope.
5. How is LTIR different from recordable rate?
LTIR only counts incidents that caused time away from work. Recordable rate includes a wider set of reportable incidents, so it often appears higher than LTIR.
6. Can I calculate LTIR when injuries are zero?
Yes. If lost time injuries are zero and total hours worked are positive, LTIR becomes zero. That still provides a useful benchmark for reporting and export.
7. Why should monthly trends be tracked?
Monthly trends reveal spikes, recurring risk periods, and seasonal exposure changes. They help supervisors investigate root causes before short-term issues become long-term performance problems.
8. Is LTIR enough on its own?
No. LTIR is helpful, but it should be reviewed alongside severity, near misses, corrective action closure, exposure hours, and root-cause findings for a fuller safety picture.