LTIFR Calculator
Formula Reference
LTIFR = (Number of Lost Time Injuries × Base Hours) ÷ Total Hours Worked| Per Million Man-Hours | 1,000,000 hrs base (most common) |
| OSHA-style | 200,000 hrs base (100 FTE / yr) |
| UK / RIDDOR-style | 100,000 hrs base |
What Counts as a Lost Time Injury?
A work-related injury or illness that results in the affected person being unable to work their next scheduled shift or work day, beyond the day the injury occurred. This is distinct from a "recordable" injury (used in TRIR), which is a broader category that also includes injuries requiring medical treatment beyond first aid, even without lost time.Methodology, interpretation & sources
Purpose. Calculate your Lost Time Injury Frequency Rate (LTIFR) — the number of lost time injuries (injuries resulting in the injured person being unable to attend their next scheduled work day/shift) standardized against total hours worked, to benchmark safety performance across sites, periods, or against industry data.
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 Reporting Standard / Base Hours Determines the standardization multiplier used in the formula., Number of Lost Time Injuries (LTIs) Injuries causing absence beyond the day of the injury — the injured person could not attend their next scheduled shift., Total Hours Worked Total exposure hours by all employees in the same period., Your Name, Email, Company Name. 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.