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SAFETY PERFORMANCE CALCULATOR

Severity Rate Calculator

Measure the severity of workplace injuries using lost workdays and total employee hours worked.

INPUT DATA

days

Total number of days lost due to work-related injuries.

hours

Total number of hours worked by all employees.

The severity rate is expressed as the number of lost workdays per 200,000 employee hours worked.

SEVERITY RATE RESULT

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No result yet

Enter lost workdays and total hours worked to calculate the severity rate.

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FORMULA

Severity Rate = (Lost Workdays × 200,000) ÷ Total Hours Worked

The severity rate shows the number of lost workdays per 200,000 employee hours worked.

IMPORTANT

Severity rate thresholds can vary by company, industry and reporting standard. Use the result together with incident details, root cause analysis and internal performance targets.

SERNEM METRIC GUIDE

What does Severity Rate measure?

SR = Lost Workdays × 200,000 / Hours
01

What is this metric?

Severity Rate measures not only incident frequency, but the amount of working time lost because of occupational injuries.

02

Why 200,000 hours?

The 200,000-hour base normalizes results so organizations of different sizes can be compared on a common scale.

03

What does 12.00 mean?

A result of 12.00 means the lost-workday impact is equivalent to 12 lost days per 200,000 employee-hours.

04

How are colors used?

Color bands are SERNEM reference categories for quick interpretation. They are not universal legal limits and should be considered with company and industry benchmarks.

Interpretation note: A lower Severity Rate generally indicates lower lost-workday impact, but it should not be used alone to judge overall safety performance. Review it together with TRIR, LTIFR, incident severity, near-miss data and root cause findings.

SEVERITY RATE REFERENCE (per 200,000 hours)

EXCELLENT
< 10
GOOD
10 – 25
FAIR
25 – 50
POOR
50 – 100
UNACCEPTABLE
> 100
Accurate measurement supports a stronger safety culture.
SERNEM Safety Platform