Injury severity rate calculator
Calculate recorded lost workdays per 1,000 hours worked, with the reporting basis clearly stated.
Enter your values
Check this tool fits your task
This version uses the 1,000-hour formula in the ILO training reference. Other schemes use different bases and day definitions; this is not a medical severity assessment.
Your result
Enter your values, or try the example to see how it works.
Calculation breakdown
What to do next
Method and sources
Severity rate = lost workdays × 1,000 ÷ hours worked. This page fixes the base at 1,000 and does not assign notional days to fatalities or permanent impairment.
ILO training package, module 2, printed page 49: severity-rate formula ↗
How to use this tool
- Check the scope and collect measured or verified input values.
- Enter values using the displayed units, then calculate.
- Read the result, calculation breakdown and next steps together.
Worked example
30 lost workdays × 1,000 ÷ 200,000 hours = 0.15 lost workdays per 1,000 hours.
The example button fills illustrative values. Where a scope confirmation is shown, check it yourself before calculating.
Method and references
Severity rate = lost workdays × 1,000 ÷ hours worked. This page fixes the base at 1,000 and does not assign notional days to fatalities or permanent impairment.
This version uses the 1,000-hour formula in the ILO training reference. Other schemes use different bases and day definitions; this is not a medical severity assessment.
Common questions
Why does another calculator show a different result?
It may use a million-hour or 200,000-hour base, or another lost-day definition. Check both before comparing.
Should I include weekends or restricted-duty days?
Use the specific reporting scheme’s definitions; do not mix workdays, calendar days and restricted-duty days.
Can this identify the severity of an individual injury?
No. It is an aggregate time-loss rate and does not diagnose or grade an injury.
Public beta · Check the method and inputs with a competent reviewer before operational use.
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