How do you calculate LTIFR?

LTIFR = (number of lost-time injuries x 1,000,000) / total hours worked. The one-million multiplier is the common international base; some organisations use 200,000 hours instead, so always state the base on the report.

How do you calculate TRIR?

TRIR = (number of recordable incidents x 200,000) / total hours worked. The 200,000 figure represents 100 full-time employees working 40 hours a week for 50 weeks, so TRIR reads as incidents per 100 workers per year.

What is the difference between TRIR and LTIFR?

TRIR counts every recordable incident, including those treated with medical attention where the person returned to work. LTIFR counts only injuries that stopped someone working their next scheduled shift, so it is always the smaller and more severe subset.

What is a good LTIFR?

It depends entirely on sector and hours base. Office and services operations often report below 1 per million hours worked, while construction, manufacturing, mining and oil and gas typically sit higher. Your own trend across four periods is more meaningful than any published average.

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🦺 Free safety calculator

TRIR, LTIFR & Severity Rate Calculator

Enter your hours worked and incident counts for the period. You will get your total recordable incident rate, lost time injury frequency rate, severity rate and near-miss reporting rate — the four figures an ISO 45001 audit and a board safety slide ask for. Everything runs in your browser; nothing is sent anywhere.

📥 Your numbers

Total hours worked in the period (employees + contractors)

Recordable incidents

Lost-time injuries

Days lost to injury

Near misses reported (optional)

TRIR (per 200,000 hours): 2.86
LTIFR (per 1,000,000 hours): 4.76
Severity rate (days lost per 1,000,000 hours): 73.8
Near-miss reporting rate (per 200,000 hours): 22.9

On average each lost-time injury cost 15.5 working days. That average is the sentence a board understands — a rising severity rate with a flat LTIFR means fewer injuries but harder ones.

📐 The formulas

TRIR = (Recordable incidents × 200,000) ÷ Hours worked
LTIFR = (Lost-time injuries × 1,000,000) ÷ Hours worked
Severity rate = (Days lost × 1,000,000) ÷ Hours worked
Near-miss rate = (Near misses × 200,000) ÷ Hours worked

200,000 — one hundred full-time workers at 40 hours a week for 50 weeks. It makes TRIR read as "incidents per 100 workers per year".
1,000,000 — the common international base for LTIFR. Some organisations use 200,000 instead, which produces a number five times smaller. Always print the base beside the rate.
Hours worked — actual hours on the job for employees and contractors. Leave, public holidays and unworked scheduled hours are excluded.
Lost-time injury — an injury after which the person could not work their next scheduled shift. Restricted-duty cases are recordable but usually not lost time.

🧾 Worked example

A plant records 420,000 hours worked in the year, with 6 recordable incidents, 2 of them lost-time injuries costing 31 days between them, and 48 near misses reported.

1. TRIR = (6 × 200,000) ÷ 420,000 = 2.86
2. LTIFR = (2 × 1,000,000) ÷ 420,000 = 4.76
3. Severity rate = (31 × 1,000,000) ÷ 420,000 = 73.8
4. Average days per lost-time injury = 31 ÷ 2 = 15.5

The board line is not "LTIFR is 4.76". It is: two injuries stopped people working, at an average of fifteen days each, while near-miss reporting rose — meaning the reporting culture is improving faster than the hazard control is.

👀 How to read the four numbers together

TRIR falling, LTIFR flat — you are preventing minor incidents but not the serious ones. Look at high-energy hazards, not housekeeping.
LTIFR flat, severity rising — fewer but harder injuries. Usually plant, vehicles or working at height.
Near-miss reporting rising, TRIR falling — the healthiest pattern there is. Say so explicitly in the report, otherwise a board reads more reports as more danger.
Everything at zero — auditors treat a perfect record with no near-miss reports as an under-reporting risk, not a triumph.

❓ Common questions

What is the difference between TRIR and LTIFR?: TRIR counts every recordable incident, including ones where the person came back to work. LTIFR counts only injuries that stopped someone working their next scheduled shift, so it is the smaller, more serious subset.
What is a good LTIFR?: It depends on your sector and your hours base, and published averages vary widely by country and reporting rules. Compare yourself against your own four previous periods first, and only then against a benchmark whose definition you have read.
Should contractors be included?: Under ISO 45001 you are responsible for workers under your control, so include contractor hours and contractor incidents together. If you must report them separately, publish both figures and the combined one.
How often should safety rates be calculated?: Monthly for the site team so trends surface early, and rolling twelve months for the board — a single month in a small operation swings wildly on one incident.