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Calculating Your Company's Lost Time Injury Frequency Rate

By Adrian Bartha
Published: March 13, 2017 | Last updated: February 27, 2022 12:41:27
Key Takeaways

Calculating your company's LTIFR can reveal information that will help you assess the effectiveness of your health and safety program.

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Incident rates are a lagging indicator of safety - a representation of an organization's past performance. That makes them an imperfect but useful measure of a safety program's effectiveness. OSHA and other regulatory agencies also use this data to determine where industries may need to enhance their safety programs.

Safety professionals should be well versed in these measures and have a working knowledge of how to calculate them. Not only because executives will ask for these numbers, but because it's a good way to take the pulse of safety on the worksite.

This article will go over what the Lost Time Injury Frequency Rate (LTIFR) represents, how to calculate it, and why every company should figure out theirs.


What Is a Lost Time Injury (LTI)?

The first step to understanding the Lost Time Injury Rate is to understand its basic building block: the Lost Time Injury (LTI).

It can also be referred to as a Lost Time Incident or a Lost Time Case. No matter the label, it refers to the same thing: any injury sustained by a worker that will ultimately lead to the loss of productive work time, either in the form of worker delays or absenteeism.

What Is Lost Time Injury Frequency Rate (LTIFR)?

A frequency rate indicates how many events have happened over a given period by a standardized number of hours worked.

The Lost Time Injury Frequency Rate (LTIFR), then, refers to the number of Lost Time Injuries that occurred within a given accounting period, relative to the total number of hours worked within the same accounting period. It measures the loss of shift work due to an injury on the job site resulting in the employee missing one shift.

For the purposes of this definition, Lost Time Injuries are defined as those that occurred in the workplace and resulted in an employee's inability to work the next full workday.

Calculating Your Company's LTIFR

The formula for calculating Lost Time Injury Frequency Rates is very simple. In many countries, the figure is typically calculated per million hours worked.

The formula is given as:

(Number of lost-time injuries in the accounting period x 1,000,000) / (Total hours worked in the accounting period)

To make it simpler, consider the following example:


Assume that your manager wants to know how many LTIs occurred over the last year per 1,000,000 hours worked.

First, you need to determine the number of LTIs that happened during that period, as well as the number of hours worked. Information regarding the number of LTIs should be readily available from your company’s workers compensation claims manager or insurance company. Data regarding the number of hours worked over the period can be obtained from your company’s payroll department.

Then, multiply the number of Lost Time Injuries by 1,000,000 and then divide the result by the number of hours worked.

The result obtained is the LTIFR.

Using an example with actual numbers, we will use the above formula to arrive at the LTIFR.

Suppose, there were eight LTIs in the past year and 2,915,638 hours worked.

  • We would begin by multiplying the eight LTIs by 1,000,000.
  • Then, we would divide the result by the total number of hours worked (2,915,638 hours) as shown below:
    • (8 x 1,000,000) / 2,915,638
    • 8 x 1,000,000 = 8,000,000
    • 8,000,000 / 2,915,638 = 2.74

Now that we know that the company’s LTIFR is 2.74, what does it mean? It indicates that your company experienced 2.74 lost time injuries for every one million hours worked over the past year.

Which Injuries Are Considered LTIs?

For an injury to count as a Lost Time Injury, it must meet the criteria for an OSHA recordable injury. OSHA categorizes an incident as recordable if it falls under any of the following descriptions:

  • Any work-related fatality
  • Any work-related injury or illness that results in loss of consciousness, days away from work, restricted work, or transfer to another job
  • Any work-related injury or illness requiring medical treatment beyond first-aid
  • Any work-related diagnosed case of cancer, chronic irreversible diseases, fractured or cracked bones or teeth, and punctured eardrums
  • Special recording criteria for work-related cases involving: needle-sticks and sharps injuries, medical removal, hearing loss, and tuberculosis

The clearest cases of Lost Time Injuries are those that result in the worker requiring time away from work to recover. However, injuries that prevent the worker from performing their regular duties or require their work to be modified for the duration of the recovery are also considered LTIs. Even if the injured worker comes to work the next day, their injury might nevertheless constitute an LTI.

It is also important to note that an injury is only a Lost Time Injury if it affects the employee's work for at least one full day or shift following the incident. Although work-related injuries typically result in some loss of productivity on the days that they occur, this same-day productivity loss does not count as an LTI.

The most common type of Lost Time Injury are musculoskeletal disorders, such as sprains and strains or muscle tears to the back, shoulder, neck, upper arm, and ankle.

(Learn about the Risk Factors for Developing Musculoskeletal Disorders)

Best Practices for Reporting LTIs

Here are a few tips to remember when reporting a Lost Time Injury:

  • All LTIs should be reported verbally within one hour of their occurrence or as soon as possible
  • A written report should be forwarded to the health and safety representative by the close of business on the same day
  • The report must be supported by a medical certificate from a registered medical practitioner declaring that the employee is unfit to perform their regular job duties

Why It's Important to Calculate LTIFRs

Over time, organizations that keep track of their Lost Time Injury Frequency Rates can gauge the effectiveness of their safety management systems and workplace safety initiates.

Additionally, since regulatory bodies like OSHA use metrics like LTIFR, organizations can benchmark their health and safety performance against OSHA’s statistics for their industry.

And of course, a reduction in the company's Lost Time Injury Frequency Rate is a promising indicator that their safety program is working as intended.

There is no shortcut to getting a lower LTIFR. The only way to improve it is to take steps to protect workers and make the workplace safer. This means provide comprehensive training to workers, supplying them with adequate PPE, and ensuring that they are not overworked.

No safety program is perfect. Continuous improvement is the name of the game. And thsoe who succeed at it should be able to track their success in part by seeing their Long Term Injury Frequency Rate gradually going down.


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Written by Adrian Bartha | Chief Executive Officer

Profile Picture of Adrian Bartha
Adrian Bartha is the CEO of eCompliance, which he joined in 2012 after experiencing first-hand how a workplace incident affected a power and utilities company which he led as a member of the Board of Directors. Previously, Adrian was an investment professional for a $5 billion dollar private equity firm investing in energy, construction, and transportation infrastructure companies across North America. When Adrian is out of the office, he can be found riding his futuristic motorcycle and wearing his RoboCop helmet.
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