A lost time injury (LTI) is a work-related injury or illness that keeps an employee from working at least one full scheduled shift or day after the day it occurred. LTIs are a common lagging safety metric, usually reported as a count and as a lost time injury frequency rate (LTIFR) that compares injuries to hours worked.
The term is widely used by multinational companies, contractors and safety prequalification programs. In the United States, the closest regulatory equivalent is the OSHA "days away from work" case, so it helps to understand how the two concepts line up.
What Is a Lost Time Injury (LTI)?
An LTI is an injury or occupational illness that results in time lost from work beyond the day of the incident. The employee may be off for one day or for months. Fatalities are often counted as LTIs as well, although some organizations report them separately.
LTI is not a term defined in OSHA regulations. Definitions vary by company, industry body and country, so the exact threshold matters. The most common definition counts any case where the worker cannot return for their next full scheduled shift. Some organizations also treat restricted duty as lost time, while others do not.
How LTI relates to OSHA recordkeeping
Under OSHA's general recording criteria at 29 CFR 1904.7, a work-related case that results in days away from work is recordable and must be entered on the OSHA 300 Log. Key OSHA counting rules include:
- Do not count the day the injury or illness occurred.
- Count calendar days the employee was unable to work, including weekends and holidays, not just scheduled workdays.
- Count days a physician or other licensed health care professional recommends the employee stay home, even if the employee comes to work anyway.
- Stop counting at 180 days away from work.
Every OSHA days away case is generally an LTI, but not every recordable injury is an LTI. Cases involving only medical treatment or only restricted work are recordable but usually not lost time.
Why Lost Time Injuries Matter
LTIs represent the more serious end of workplace harm. They affect the injured worker's health and income, and they create direct and indirect costs for the employer, including workers' compensation claims, replacement labor, overtime, lost productivity and administrative time.
LTI performance also influences business outcomes. Clients and general contractors often ask for LTI counts and frequency rates during bid prequalification. Insurers consider claim severity and frequency when setting premiums, and a history of lost time claims can raise an employer's experience modification rate.
How to Calculate the Lost Time Injury Frequency Rate (LTIFR)
LTIFR normalizes the number of LTIs by hours worked, so sites of different sizes can be compared. Two multipliers are common:
- Per 1,000,000 hours: widely used in Australia, the UK, Europe and international oil and gas.
- Per 200,000 hours: used in the United States, matching OSHA incidence rates. 200,000 hours represents 100 full-time employees working 40 hours a week for 50 weeks.
LTIFR = (number of LTIs × 1,000,000) ÷ total hours worked
US-style lost time rate = (number of LTIs × 200,000) ÷ total hours worked
Worked example
A hypothetical manufacturing company has 250 employees who worked 500,000 hours last year. It recorded 3 lost time injuries.
- LTIFR per million hours = (3 × 1,000,000) ÷ 500,000 = 6.0
- Rate per 200,000 hours = (3 × 200,000) ÷ 500,000 = 1.2
Both numbers describe the same performance. Always state which multiplier you use when sharing results, because mixing them leads to misleading comparisons.
Accurate hours matter as much as accurate injury counts. Use actual hours worked by all employees, including overtime, and exclude paid time off such as vacation, holidays and sick leave. This matches the approach in the OSHA Form 300A instructions. If temporary or contract workers you supervise day to day are included in your injury count, include their hours too, or the rate will be overstated.
Lost time severity rate
Frequency does not show how serious injuries are. A severity rate adds that context:
Severity rate = (total days lost × 200,000) ÷ total hours worked
If the same company lost 45 days across its three LTIs, its severity rate would be (45 × 200,000) ÷ 500,000 = 18.0 days lost per 100 full-time workers.
LTI vs. Related Safety Metrics
LTI vs. DART rate
The DART rate counts cases involving days away, restricted work or job transfer. It is broader than LTI, because it includes restricted duty cases where the employee still comes to work.
LTI vs. TRIR
The total recordable incident rate includes all OSHA recordable cases: days away, restricted work, medical treatment beyond first aid, loss of consciousness and significant diagnosed conditions. LTIs are a subset of recordables.
LTI vs. first aid case
A first aid case involves only treatments on OSHA's first aid list, such as bandages or non-prescription medication at non-prescription strength. If the worker returns to their next shift, it is neither recordable nor lost time.
Examples of Lost Time Injuries
- A warehouse worker strains their back lifting a carton, and a physician recommends three days off work.
- A maintenance technician suffers a hand laceration that requires surgery and two weeks of recovery.
- A driver fractures an ankle stepping down from a truck cab and is off work for six weeks.
- An employee develops a work-related respiratory illness and misses several shifts on medical advice.
By contrast, a worker who receives stitches and returns for the next shift has a recordable injury, but not an LTI under the most common definition.
How to Reduce Lost Time Injuries
- Report and investigate every incident. Capture near misses and minor injuries, not only LTIs, so you see patterns early.
- Find root causes. Use a structured root cause analysis to look beyond individual error to equipment, procedures and supervision.
- Control top hazards. Apply the hierarchy of controls to the tasks that produce the most serious injuries, such as manual handling, falls and machine contact.
- Track leading indicators. Monitor inspections, training and corrective action closure as early warnings.
- Manage return to work. Offer suitable transitional duties where medically appropriate and coordinate closely with treating providers and insurers.
Common Mistakes to Avoid
- Pressuring injured workers to return early to protect an LTI-free record. This harms workers, can violate OSHA's anti-retaliation provisions and hides real risk.
- Using inconsistent definitions across sites or contractors, which makes comparisons meaningless.
- Relying on LTIs alone. LTIs are rare at small sites, so year-to-year changes can be random noise. Combine them with broader measures.
- Counting only scheduled days when reporting OSHA days away. OSHA requires calendar days.
How SMS360 Helps
SMS360's Incident Management module gives teams one place to report injuries, record days away and restricted time, and assign investigations and corrective actions. Records stay linked to each case, so safety managers can track LTIs, review trends on dashboards and prepare OSHA logs from consistent data. Mobile reporting helps supervisors capture incidents promptly from the field.
Frequently Asked Questions
What counts as a lost time injury?
A lost time injury is a work-related injury or illness that prevents an employee from working at least one full scheduled shift or day after the day of the incident. Most organizations exclude the day the injury happened. Some include fatalities and some count restricted duty as lost time, so check the definition your company, client or industry body uses before reporting.
How do you calculate LTIFR?
Multiply the number of lost time injuries by 1,000,000, then divide by the total hours worked in the same period. For example, 2 LTIs in 400,000 hours gives an LTIFR of 5.0. In the United States, many companies use 200,000 instead of 1,000,000 to match OSHA incidence rates, which would give 1.0 in the same example.
Is a lost time injury the same as an OSHA recordable?
No. Every lost time injury that is work-related is generally OSHA recordable as a days away case, but many recordable cases are not lost time. Injuries that need only medical treatment beyond first aid, or that result only in restricted work or job transfer, are recordable without being LTIs. LTIs are a subset of recordable injuries.
Does the day of the injury count as lost time?
Under OSHA recordkeeping rules, the day the injury or illness occurred is not counted as a day away from work. Counting begins the following day and includes all calendar days the employee cannot work, up to a cap of 180 days. Most LTI definitions follow the same approach, so a worker who leaves early on the day of injury but returns the next shift is not an LTI.
