Understanding Lost Time Injury Rate
How we calculate. LTIR = (LTI count × 200,000) ÷ total hours worked. See our methodology and accuracy policy .
Real-world scenario: A typical Lost Time Injury Rate case uses lost-time injuries 1 and hours worked 400000. Enter the same figures below to reproduce the worked path.
What is Lost Time Injury Rate?
A severity-focused safety rate that pairs with TRIR. LTIR counts injuries with days away; TRIR includes broader recordables.
- LTI definition per safety policy
- Same hours base as TRIR when comparing
- Result is a rate, not a percent
The Formula
Worked Example
Common Use Cases
- Safety scorecards: severity rate
- Prequalification: LTI history
- Project reviews: TRIR vs LTIR
Pro Tips
- Align LTI criteria with insurer/owner
- Report beside TRIR
- Not a substitute for legal reporting
| Scenario | When to use |
|---|---|
| Percent of a number | Finding a part of a whole (tax, tip, score) |
| Percent change | Comparing old vs new values |
Limitations: Lost Time Injury Rate results are educational construction planning aids—not engineering, safety, legal, or cost-estimating advice. Confirm definitions with your project controls, safety, and contract documents. For earned-value SPI/CPI see the Professional hub.
Common mistakes
- Swapping part and whole: The denominator must be the full total, not a subset.
- Rounding too early: Carry extra decimal places through multi-step work before rounding the final percent.
- Mixing percent and decimal forms: Enter rates in the format the calculator labels expect.
The worked example for lost time injury rate was verified with the calculator form on this page—enter the same values to confirm the result.
When to use this calculator
- Use this page when your wording matches lost time injury rate and the form labels on screen.
- Use percent of a number for “what is X% of Y?” problems.
- Use number is what percent when you know part and whole and need the percent.
Still unsure about lost time injury rate? Start with the quick answer above, then open the linked calculator that matches your wording.
❓ Frequently Asked Questions
How do I use this lost time injury rate calculator?
For lost time injury rate, enter the values labeled on the form, then press Calculate. Compare the result to the worked example on this page.
What formula does this page use?
See the quick answer and formula box above for lost time injury rate—the same percentage calculator expression is applied to your inputs.
What if my result looks wrong?
When checking lost time injury rate, re-check part vs whole (or rate vs base), rounding, and whether percents were entered as 25 rather than 0.25 when the form expects percents.
Authoritative References
For construction project controls and safety rate concepts, consult: