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LTIFR and TRIFR calculator
LTIFR is the number of lost time injuries per million hours worked: LTIs x 1,000,000 / hours worked. TRIFR counts every recordable injury (lost time, medical treatment and restricted work) on the same basis.
Enter your injuries and hours below. No hours on hand? Estimate them from headcount.
Injuries in the period
Hours worked in the period
Rate basis
Your rates
LTIFR
3.66per million hoursLTIs x 1,000,000 / hours worked3 x 1,000,000 / 820,000 = 3.66
TRIFR
12.20per million hours(LTIs + MTIs + RWIs) x 1,000,000 / hours worked(3 + 5 + 2) x 1,000,000 / 820,000 = 12.20
Report the rate with its period and whether contractors are included, and track it on a rolling 12 months so one bad month does not swing it.
Worked example
A 420-person business over 12 months
| Measure | Count | Working | Rate |
|---|---|---|---|
| LTIFR | 3 lost time injuries | 3 x 1,000,000 / 820,000 | 3.66 |
| TRIFR | 3 LTI + 5 MTI + 2 RWI = 10 | 10 x 1,000,000 / 820,000 | 12.20 |
Hours: 820,000 worked across employees and contractors in the 12 months.
Definitions
What counts as each injury type
| Type | Usually means | Counts in |
|---|---|---|
| Lost time injury (LTI) | The worker could not work at least one full shift after the day of the injury. Fatalities are included. | LTIFR and TRIFR |
| Medical treatment injury (MTI) | Treated by a doctor or other professional beyond first aid, with no lost shift. | TRIFR |
| Restricted work injury (RWI) | The worker stayed at work but could not do their normal duties, e.g. on suitable duties. | TRIFR |
| First aid injury | Treated on site with first aid only. | Neither |
Definitions vary between organisations and contracts. Write yours down, apply it the same way every month, and state it next to the rate.
Questions
Common questions
How do you calculate LTIFR?
Multiply the number of lost time injuries in the period by 1,000,000, then divide by the total hours worked in the same period. Three lost time injuries in 820,000 hours is 3 x 1,000,000 / 820,000 = 3.66.
What is the difference between LTIFR and TRIFR?
LTIFR counts only injuries that cost at least a full shift. TRIFR counts every recordable injury: lost time, medical treatment beyond first aid, and restricted work. TRIFR is always equal to or higher than LTIFR, and it moves sooner, because there are more medical treatment injuries than lost time ones.
Why per million hours?
Dividing by hours worked lets a 40-person site and a 4,000-person business be compared on the same scale. Australia, New Zealand and the UK use 1,000,000 hours. US OSHA rates use 200,000 hours, which is roughly 100 full-time workers for a year.
Should contractor injuries and hours be included?
Include both or neither. Counting contractor injuries against employee-only hours inflates the rate, and the reverse hides harm. Most principal contractors report a combined rate and say so next to the number.
What is a good LTIFR?
It depends on the industry and on how strictly lost time is defined, so compare against your own trend and your sector rather than a single number. A falling rolling 12-month rate is a better sign than a low rate in one month.
I don't track hours worked. Can I still work out a rate?
Yes. Multiply the number of workers by their average weekly hours and the weeks actually worked after leave. It is an estimate, so note that on the report and switch to payroll or timesheet hours when you can.
Next step, free
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Umbrella works out LTIFR and TRIFR from your incident register and hours, by site and on a rolling 12 months, and puts them in the board report automatically.
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