HS Easy practical guide
What is LTIFR and how to calculate it
A simple guide for safety managers on defining, calculating and using lost time injury frequency rate (LTIFR), with practical data checks and limitations.
The short answer
LTIFR is a frequency measure for lost-time injuries against hours worked. Calculate it as lost-time injuries divided by total hours worked, then multiply by your chosen reporting multiplier. Use a written definition and consistent data rules before comparing results.
LTIFR can help safety teams spot trends and focus investigation and prevention work. It is only as reliable as the injury and hours data behind it. Definitions and multipliers can vary between organisations, so agree them in writing and do not compare rates unless the calculation basis is the same.
What LTIFR measures
LTIFR means lost time injury frequency rate. It expresses the number of injuries meeting your organisation’s lost-time definition relative to hours worked. It is a performance indicator, not a measure of legal compliance, fault or the full level of workplace risk.
- Count only cases that meet your agreed lost-time definition.
- Use the same reporting period for injuries and hours.
- Record the calculation basis alongside every reported rate.
The LTIFR formula
Use: LTIFR = (number of lost-time injuries ÷ total hours worked) × multiplier. The multiplier is a number your organisation chooses for reporting. Keep it unchanged when tracking a trend, and state it whenever you share the result.
- LTI is the number of qualifying lost-time injuries.
- Hours worked should cover the same people and period.
- Multiplier must be agreed and consistently applied.
Worked calculation
If a team records 2 qualifying lost-time injuries and 400,000 hours worked, its rate is (2 ÷ 400,000) × M. The result is 0.000005 × M. Insert your organisation’s agreed multiplier to produce the published LTIFR.
- Check the injury count before closing the reporting period.
- Check that hours are complete and not duplicated.
- Retain the inputs so the rate can be checked later.
Define the data before you count
Write a local rule for what counts as lost time, when a case enters the measure and how revised outcomes are handled. The supplied recordkeeping source supports recording work-related cases, days away and changed outcomes, but it is an OSHA source and does not set UK LTIFR rules.
- Update records when the outcome of a case changes.
Use LTIFR with other evidence
A low LTIFR does not prove that work is safe. A rate can move because of a small workforce, incomplete hours or a different case definition. Review incident causes, near misses, inspections, corrective actions and exposure to serious hazards alongside the rate.
- Investigate each significant event, not only the monthly figure.
- Compare like-for-like sites, work and reporting periods.
- Look for repeated causes and overdue corrective actions.
Key takeaways
LTIFR is most useful when it is calculated consistently and used as one part of a wider safety review. Agree the lost-time definition, multiplier, worker population and hours source first. Keep the raw data and investigate the events behind the number, especially where serious potential exists.
Frequently asked questions
What hours should be included in LTIFR?
Use total hours worked for the same worker group and reporting period as the injury count. Set a written rule for employees, agency workers and contractors, then apply it consistently. Incomplete or mixed-population hours can distort the rate.
Can LTIFR be compared between sites?
Only with caution. Compare sites when they use the same lost-time definition, reporting period, multiplier, worker population and hours method. Different work activities and small hour totals can also make direct comparisons misleading.
Does a low LTIFR mean a workplace is safe?
No. LTIFR only reflects qualifying lost-time injuries relative to hours worked. Review near misses, high-potential events, inspections, hazards, corrective actions and the quality of reporting as well.
Related HS Easy resources
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General information only. Review current HSE guidance, your own procedures and the conditions at your workplace.