Lost Time Injury Rate Calculator

Enter your lost time cases and total hours worked to calculate your LTIR, safety score, injury frequency index, and benchmark comparison.
Luis GonzalezCreated by Luis GonzalezLast updated:

How to Use This Calculator

  1. 1

    Enter Lost Time Cases

    Input the total number of work-related injuries or illnesses that resulted in an employee missing at least one day of work beyond the day of the injury, for example, 4 cases.

  2. 2

    Specify Total Hours Worked

    Enter the cumulative number of hours worked by all employees during the measurement period (e.g., a quarter or year), for example, 420,000 hours.

  3. 3

    Review Your Safety Metrics

    The calculator displays your Lost Time Injury Rate, vs. Industry Benchmark comparison, Safety Score, Injury Frequency Index, Hours Per Incident, and Exposure Level. The insights panel shows workforce equivalent, incident interval, and what it takes to reach the benchmark.

Example Calculation

A construction company wants to assess its safety performance for the past year. They recorded 4 lost time cases among their employees who collectively worked 420,000 hours.

Lost Time Cases

4

Total Hours Worked (hr)

420,000

Results

LTIR

1.90

vs. Benchmark

0.40 above 1.5

Safety Score

61.9/100

Injury Frequency Index

9.52

Hours Per Incident

105,000 hr

Exposure Level

Low

Tips

Implement Proactive Safety Training

Reduce LTIR by investing in continuous, job-specific safety training. At an LTIR of 1.90, reducing just 1 case (from 4 to 3) would lower the rate to 1.43 — below the 1.5 benchmark.

Conduct Thorough Incident Investigations

Investigate every lost time incident to identify root causes, not just immediate triggers. With 4 cases over 420,000 hours, each incident occurs roughly every 105,000 hours — investigate what differs between safe and unsafe periods.

Promote Near-Miss Reporting

Encourage employees to report all near-misses without fear of reprisal. These close calls are valuable leading indicators that, if addressed, can prevent the next lost time injury and improve your Safety Score.

Benchmarking Safety: Your Lost Time Injury Rate Calculator

The Lost Time Injury Rate (LTIR) Calculator helps businesses assess workplace safety performance by computing the LTIR per 200,000 hours worked.

This metric enables comparison against industry benchmarks, highlighting areas for improvement.

For example, a construction company with 4 lost time cases over 420,000 hours worked has an LTIR of 1.90, which is 0.40 above the 1.5 industry benchmark.

Enhancing Safety Culture in Construction

Safety culture is paramount in the construction industry, which historically faces some of the highest injury rates.

The Occupational Safety and Health Administration (OSHA) sets and enforces safety standards, and companies strive for LTIRs well below industry averages.

While the general industry LTIR often hovers under 1.0, construction may see slightly higher averages, with companies consistently aiming for less than 2.0.

Proactive measures include daily toolbox talks, comprehensive PPE programs, regular site inspections, and continuous hazard identification training.

A company reporting 4 cases over 420,000 hours with an LTIR of 1.90 is close to the 1.5 benchmark but has room for improvement.

The Formula for Lost Time Injury Rate (LTIR)

The LTIR formula normalizes the number of incidents against total hours worked to allow fair comparisons across different company sizes and reporting periods.

LTIR = (Number of Lost Time Cases x 200,000) / Total Hours Worked

Here:

  • Number of Lost Time Cases refers to incidents resulting in at least one full day of missed work beyond the day of the injury.
  • Total Hours Worked is the sum of all employee hours during the period.
  • 200,000 is a constant representing the hours 100 full-time employees work in a year (100 x 40 hours/week x 50 weeks).

Additional metrics calculated:

  • Safety Score = max(0, 100 - LTIR x 20) — a 0-100 scale
  • Injury Frequency Index = (Cases / Total Hours) x 1,000,000 — incidents per million hours
  • Hours Per Incident = Total Hours Worked / Number of Cases
💡 For other critical safety assessments in construction, our Concrete Slab Load Capacity Calculator can help ensure structural integrity.

Calculating a Construction Company's LTIR

A construction company recorded 4 lost time cases with employees who collectively worked 420,000 hours during the past year.

  1. Apply the LTIR Formula:

    • LTIR = (4 cases x 200,000) / 420,000 hours
    • LTIR = 800,000 / 420,000
    • LTIR = 1.90

  2. Calculate Safety Score:

    • Safety Score = 100 - (1.90 x 20) = 100 - 38.1 = 61.9/100

  3. Calculate Injury Frequency Index:

    • IFI = (4 / 420,000) x 1,000,000 = 9.52 per million hours

  4. Calculate Hours Per Incident:

    • 420,000 / 4 = 105,000 hours between incidents

The company's LTIR is 1.90, which is 0.40 above the 1.5 industry benchmark.

The Safety Score of 61.9/100 indicates moderate performance.

To reach the benchmark, they would need to reduce to 3 or fewer cases per year.

💡 For estimating material needs for construction projects, our Concrete Volume Calculator (Column) helps plan resources efficiently.

Construction Industry Safety Benchmarks and Performance

According to Bureau of Labor Statistics (BLS) and OSHA data, the average LTIR for general private industry is around 0.9, while the construction sector typically hovers between 1.5 and 2.5 per 200,000 hours worked.

A company with an LTIR below 1.5 has strong safety performance.

An LTIR between 1.5 and 2.5 indicates moderate performance with room for improvement, while anything above 2.5 signals poor performance requiring immediate intervention.

An LTIR of 1.90 places a construction company near the national average, suggesting a solid foundation but highlighting opportunities to improve.

Frequently Asked Questions

What is the Lost Time Injury Rate (LTIR)?

The Lost Time Injury Rate (LTIR) measures the frequency of workplace injuries resulting in missed work time, calculated per 200,000 hours worked (representing 100 full-time employees for one year). A lower LTIR means better safety performance. With 4 cases over 420,000 hours, the LTIR is 1.90.

Why is LTIR important for workplace safety?

LTIR provides a standardized measure of how often serious injuries occur, enabling comparisons across company sizes and time periods. A high LTIR signals safety deficiencies, leading to increased workers' compensation costs, lost productivity, and potential OSHA fines. The 1.5 industry benchmark helps organizations gauge whether they need improvement.

How does OSHA use LTIR?

OSHA uses similar rates like TRIR (Total Recordable Incident Rate) and DART (Days Away, Restricted, or Transferred) to evaluate employer safety performance. These rates help OSHA prioritize inspections and enforce workplace safety standards. An LTIR of 1.90 in construction would be closely scrutinized, as it exceeds the general industry benchmark.

What is the Safety Score and how is it calculated?

The Safety Score is a 0-100 scale derived from the LTIR: Safety Score = 100 - (LTIR x 20). An LTIR of 1.90 yields a score of 61.9/100 (moderate performance). A score of 80+ indicates excellent safety, 50-80 is moderate, and below 50 signals poor performance needing immediate action.