What is LTIFR (Lost Time Injury Frequency Rate)?
The Lost Time Injury Frequency Rate (LTIFR) is the number of lost-time injuries per million hours worked. It is calculated as lost-time injuries multiplied by 1,000,000, divided by the total hours worked in the same period. Like TRIR, it is a lagging indicator, and rates can only be compared when cases are defined the same way.
Key facts
- Formula: (lost-time injuries × 1,000,000) ÷ total hours worked in the period.
- It counts injuries, not the number of days lost.
- EU-OSHA lists lost-time injuries among lagging indicators.
- U.S. rates such as TRIR and DART use a 200,000-hour base instead, so they are not directly comparable with LTIFR.
How do you calculate LTIFR?
Multiply the number of lost-time injuries in the period by 1,000,000, then divide by the total hours worked in the same period. For example, 4 lost-time injuries over 800,000 hours worked gives (4 × 1,000,000) ÷ 800,000 = 5.
What counts as a lost-time injury?
There is no single definition used everywhere. Before comparing an LTIFR with another site, company or published figure, check the absence threshold that makes an injury lost-time, whether illnesses are included, and whose hours are counted, for example contractors.
How does LTIFR differ from TRIR and DART?
TRIR and DART express cases per 100 full-time workers using a 200,000-hour base. LTIFR uses one million hours. DART also counts restricted-duty and job-transfer cases, which an LTIFR usually leaves out.
Frequently asked questions
Does LTIFR measure how long workers are absent?
No. It counts lost-time injuries; it does not add up the length of the absences.
Is LTIFR a leading or a lagging indicator?
Lagging. It counts injuries that have already happened, and EU-OSHA lists lost-time injuries among lagging indicators.
Sources
- Glossary: Lost Time Injury Frequency Rate (LTIFR), Safe Work Australia (accessed October 28, 2026)
- Key performance indicators, European Agency for Safety and Health at Work (OSHwiki) (accessed October 28, 2026)
- How To Compute Your Firm’s Incidence Rate for Safety Management, U.S. Bureau of Labor Statistics (accessed October 28, 2026)
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