What this calculator does
TRIFR stands for Total Recordable Injury Frequency Rate, a standard workplace health-and-safety metric used across construction, mining, manufacturing and many other industries to compare injury performance between sites, contractors or time periods. It counts every recordable injury, meaning anything requiring medical treatment beyond first aid, not only injuries serious enough to cause lost time.
The figure is expressed per million hours worked rather than as a raw count, because a raw injury count on its own says nothing about exposure. A site running 50,000 hours a month with two injuries is performing far worse than a site running 500,000 hours a month with the same two injuries, and TRIFR is what makes that comparison fair.
The formula
Divide the number of recordable injuries by the total hours worked over the same period, then multiply by 1,000,000 to express the rate per million hours worked, which is the industry-standard base for this figure.
| Term | Meaning |
|---|---|
| TRIFR | Total Recordable Injury Frequency Rate: (recordable injuries ÷ hours worked) × 1,000,000. |
| Recordable injury | Any workplace injury requiring treatment beyond basic first aid, including medical treatment, restricted duties or lost time. |
| Hours worked | The total hours worked by everyone covered by the measurement, across the same period as the injury count. |
The inputs explained
| Field | What to enter |
|---|---|
| Recordable injuries | The number of recordable injuries logged over the period being measured. |
| Total hours worked (hours) | Total hours worked by the workforce over that same period, summed across everyone covered. |
When to use it
Comparing sites or contractors
A head office overseeing several sites of very different sizes uses TRIFR rather than raw injury counts, since it accounts for how many hours were actually worked at each one.
Tracking safety performance over time
Recalculating TRIFR each reporting period, using that period’s injuries and hours, shows whether safety performance is improving or slipping, independent of whether the workforce grew or shrank.
Reporting to a client or regulator
Many head contracts and tender processes ask for TRIFR as a standard safety benchmark, since it lets a client compare bidders on a like-for-like basis.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How TRIFR changes with the number of recordable injuries, at a fixed workforce size
The same 1,000,000 hours worked, across a range of recordable injury counts.
How TRIFR changes as hours worked increase, at a fixed number of injuries
The same 5 recordable injuries, spread across a range of total hours worked.
Questions
What counts as a recordable injury?
Broadly, any workplace injury or illness requiring medical treatment beyond basic first aid, including cases involving restricted duties or lost time. The exact definition can vary by jurisdiction and industry scheme, so check the standard your organisation reports against before logging a borderline case.
What is a good TRIFR?
It depends heavily on the industry: office-based work and heavy construction have very different baseline risk levels, so there is no single benchmark worth quoting. The more useful comparison is your own TRIFR over time, or against other sites or contractors doing similar work.
Is TRIFR the same as LTIFR?
No. LTIFR (Lost Time Injury Frequency Rate) counts only injuries that caused time off work, while TRIFR counts all recordable injuries, including those treated with restricted duties but no lost time. TRIFR is generally the broader, and therefore higher, figure.
Why per million hours rather than per employee?
Hours worked accounts for part-time staff, overtime and contractors more accurately than a headcount does, and per-million-hours is the convention most safety regulators and industry bodies report against, which keeps figures comparable across organisations.
For a general rate expressed as a percentage rather than per million hours, see the conversion rate calculator.