How do I calculate the lost time injury rate?

Short answer: multiply your case count by the hours basis your audience expects (200,000 for the OSHA convention, 1,000,000 for the EU/ISO convention), then divide by total hours actually worked in the period. LTIR counts only injuries with lost work days; TRIR counts every recordable case. The rate is meaningless without stating the basis next to it, because a rate on 200,000 hours is five times the same rate on 1,000,000 hours. Here are both formulas, a worked example, and what QuickInspect fills in for you.

The two formulas

Metric	Formula	What it counts
LTIR (Lost Time Injury Rate, also called LTIFR)	(lost time cases × basis hours) ÷ total hours worked	Only injuries that caused at least one lost work day
TRIR (Total Recordable Injury Rate, also called TRIFR or OSHA Recordable Incident Rate)	(recordable cases × basis hours) ÷ total hours worked	Fatalities, lost time cases, restricted work cases and medical treatment cases

"Total hours worked" means actual hours on the job for everyone covered by the count, including contractors if your scope includes them, not headcount and not scheduled hours. This is the number companies get wrong most often, because payroll systems track paid hours, not worked hours.

Which hours basis: 200,000 or 1,000,000

• 200,000 hours is the OSHA convention: the rough equivalent of 100 full-time workers, each working 40 hours a week for 50 weeks a year. It is the default for US-facing reports.
• 1,000,000 hours is the convention most European HSE teams, group-level dashboards and ISO 45001 audits use, because it produces a comparable rate across sites of very different sizes without decimals that are hard to read.

Both are arbitrary multipliers that turn a small fraction into a readable number. Neither is more "correct" than the other; what matters is stating which one you used and never mixing rates calculated on different bases in the same chart or benchmark.

What counts as "recordable"

Not every logged incident feeds the numerator. Against a typical nine-way incident classification, the split usually looks like this:

Classification	Feeds LTIR	Feeds TRIR
Fatality	Yes	Yes
Lost Time Case	Yes	Yes
Restricted Work Case	No	Yes
Medical Treatment Case	No	Yes
First Aid Case	No	No
Unsafe Condition / Unsafe Act (near misses)	No	No
Environmental Incident, Positive Observation	No	No

First aid cases and near misses matter for prevention, but they do not belong in either rate — mixing them in inflates the number and makes it incomparable to anyone else's.

A worked example

A 120-employee site logs 220,000 hours worked in the year, with 3 lost time cases, 2 restricted work cases and 4 medical treatment cases (9 recordable cases total, no fatalities):

Metric	On 1,000,000 hours	On 200,000 hours
LTIR	3 × 1,000,000 ÷ 220,000 = 13.6	3 × 200,000 ÷ 220,000 = 2.7
TRIR	9 × 1,000,000 ÷ 220,000 = 40.9	9 × 200,000 ÷ 220,000 = 8.2

Same site, same year, same injuries — a rate five times larger just from switching the basis. Always print the basis on the chart.

Germany's own metric: the 1000-Mann-Quote

German statutory accident insurers (Berufsgenossenschaften) do not publish LTIR or TRIR. Their own statistic is the 1000-Mann-Quote: reportable accidents (meldepflichtige Arbeitsunfälle, the same threshold as the Unfallanzeige — more than three lost days) per 1,000 full-time-equivalent workers (Vollarbeiter) per year. It answers a similar question with a different denominator: workers, not hours.

LTIR and TRIR still matter for a German or EU company for two reasons that have nothing to do with the BG: ISO 45001 clause 9.1 requires tracked OH&S performance indicators as evidence for the management review, and CSRD/ESRS S1-14 asks listed and large companies for a recordable-incident rate. Keep both a national statistic for the authorities and an international rate for the certification body and the group dashboard; they answer different questions and neither replaces the other.

How QuickInspect calculates it for you

• Worked hours in, rates out. The KPI dashboard plots cumulative LTIR/TRIR frequency-rate curves from the worked hours your company records, on the basis you configure in your regulatory settings — 1,000,000 hours (EU-style) or 200,000 hours (OSHA-style).
• Classification feeds the numerator. Every incident is logged against one of nine classifications, and the monthly chart breaks counts down by classification next to the frequency curves, so you can see whether a rate move is driven by lost time cases or restricted work.
• Targets, not just history. If an active OH&S objective sets a target for a rate, it draws as a reference line on the chart — the ISO 45001 §6.2 objective, next to the actual curve.
• Hours without manual entry. Worked hours can be pushed in from your ERP through the API (GET /v1/kpis reads the same rollup back out), so the denominator does not depend on someone remembering to type it into a spreadsheet every month.
• Everyone sees the number. The KPI dashboard, LTIR/TRIR curves included, is part of every QuickInspect plan from Free upward, scoped to the projects each person can access; the full dashboard exports as a paginated PDF for the management review, and Key Users with full company visibility can export the ESRS S1-14 datapoints for CSRD reporting.

Get the worked-hours count right and both formulas take care of themselves — the KPI dashboard does the arithmetic the moment an incident is closed and the hours are logged.