OSHA Lost Time Incident Rate Calculator

Lost-Time Incident Rate (LTIR)

The Lost Time Incident Rate (LTIR) is a key safety metric used to measure how many workplace incidents result in an employee losing time from work. In other words: when someone gets injured or falls ill on the job and cannot return to regular work (or must be assigned restricted duty), LTIR gives you a standardised way to understand how often that happens relative to total employee work hours.

Tracking your LTIR gives you insights into both safety performance and productivity impacts: every incident with lost time means cost, disruption, and possibly reputational risk.

Why the LTIR matters

• A high LTIR signals that something in your safety program may need attention: hazard controls, training or supervision might be falling short.
• When employees are away or restricted, productivity drops, safety momentum may falter, and insurance/compensation costs may rise.
• Conversely, a low and improving LTIR helps show that your safety efforts are effective and can bolster stakeholder confidence (management, workers, insurers).
• It also provides a benchmark. While “good” numbers vary by industry, having a trend line and comparing to peer or national norms helps gauge your performance.

How LTIR is calculated

Here’s the formula used in the calculator above:

LTIR = (Number of Lost-Time Cases × 200,000) ÷ Total Hours Worked

Where:

• Number of Lost-Time Cases = incidents in which an employee had to miss work or was placed on restricted duty because of a work-related injury or illness.
• Total Hours Worked = the combined hours worked by all employees over the same period (typically one year).
• The multiplier (200,000) standardises the rate to “per 100 full-time employees” (assuming 2,000 hours/year × 100 employees) so you can compare across organisations of different size.

Example:
If a company had 4 lost-time cases over a year, and employees worked 160,000 hours, the calculation would be:
(4 × 200,000) ÷ 160,000 = 5.0 LTIR
This means 5 lost-time incidents per 100 full-time employees for that year.

What is a “good” LTIR?

There’s no one-size-fits-all benchmark because industries differ so widely (construction, manufacturing, office work, etc.).
However:

• Lower figures are better: fewer incidents means better safety performance.
• Track your own LTIR over time, aim to reduce it year-on-year, and benchmark against industry averages or comparable organisations.
• Use the number as a trend indicator, not a guarantee of safety. A very low LTIR might hide unreported incidents or overly stringent classification; a single serious event can spike the metric dramatically in a small organisation.

Keys to Reducing Your LTIR

• Build a safety-first culture: Encourage every employee from frontline staff to executives to value safety. Leadership involvement, toolbox talks, visible commitment all help.
• Perform regular hazard assessments: Conduct workplace inspections, task hazard analyses and ensure controls are in place and up to date. Rotate assessment teams to maintain objectivity.
• Investigate incidents deeply: When an incident occurs, go beyond “what happened” to “why did it happen?” and “how can we prevent it happening again?”. Use root-cause methods like “black box” thinking to learn.
• Engage employees in safety: Empower workers to spot hazards, report near-misses, suggest improvements and recognise safe behaviour. Communication and engagement matter.
• Analyse your data: Don’t just compute the number track trends, segments (by shift, area, machine), and correlate with other performance indicators. Use it to drive improvement rather than merely monitor.
• Maintain consistent and accurate reporting: Ensuring data integrity (hours worked, incident classification) prevents misleading numbers and supports better decisions.

Important Considerations & Limitations

• The LTIR only measures frequency of incidents causing lost time it does not directly measure severity (how long someone was away, cost, or long-term effects).
• Smaller organisations may see wide fluctuations in LTIR due to a small number of incidents and fewer working hours interpret carefully.
• Use LTIR as one of multiple metrics (alongside severity rate, total recordable incident rate, near-miss frequency) to get a full safety performance picture.
• Always confirm that definitions of “lost time case” and “hours worked” conform with your local regulatory or internal standards.

Sources: Fluix, TRDSF, Creative Safety Supply, SafetySpace, EHS Insight, EcoOnline.