Calculate the average number of lost workdays per 100 full-time employees to measure the impact of workplace injuries.
Enter values above to see the calculation.
What is the OSHA Severity Rate?
The OSHA Severity Rate is a safety metric that describes the impact of workplace injuries and illnesses by measuring the number of lost workdays relative to the total number of hours worked by all employees. While the Total Recordable Incident Rate (TRIR) counts the frequency of incidents, the Severity Rate measures the intensity or seriousness of those incidents.
The Severity Rate Formula
The calculation is based on 100 full-time equivalent (FTE) workers, which assumes each worker works 2,000 hours per year (40 hours per week × 50 weeks).
Formula: (Total Lost Workdays × 200,000) / Total Employee Hours Worked
Key Terms Defined
Lost Workdays: The number of days an employee was unable to work or was restricted in their duties due to a job-related injury or illness.
Total Hours Worked: The actual number of hours worked by all employees (including overtime) during the specific period being measured.
200,000: The standard benchmark representing 100 full-time employees working 40 hours per week for 50 weeks a year.
Example Calculation
Suppose a manufacturing facility had 20 lost workdays last year. The total hours worked by all staff combined was 450,000 hours.
Variable
Value
Lost Workdays
20
Total Hours Worked
450,000
Severity Rate
8.89
Calculation: (20 × 200,000) / 450,000 = 8.89. This means for every 100 employees, approximately 8.89 workdays were lost due to injury severity.
Why Monitoring Severity Rates Matters
Tracking severity rates is essential for safety professionals for several reasons:
Safety Program Evaluation: A high severity rate with a low frequency rate indicates that while accidents are rare, they are very serious when they do occur.
Benchmarking: Companies use this data to compare their safety performance against industry averages.
Resource Allocation: It helps identify departments or tasks that pose the highest risk of severe injury, allowing for targeted safety investments.
Insurance Premiums: High severity rates often correlate with higher workers' compensation claims and premiums.
function calculateOSHASeverity() {
var lostDays = document.getElementById('lostDays').value;
var totalHours = document.getElementById('totalHours').value;
var resultDisplay = document.getElementById('oshaResult');
var valLostDays = parseFloat(lostDays);
var valTotalHours = parseFloat(totalHours);
if (isNaN(valLostDays) || valLostDays < 0) {
resultDisplay.innerHTML = 'Please enter a valid number for lost workdays.';
return;
}
if (isNaN(valTotalHours) || valTotalHours <= 0) {
resultDisplay.innerHTML = 'Total hours must be a number greater than zero.';
return;
}
// OSHA Severity Rate Formula: (Lost Days * 200,000) / Total Hours
var severityRate = (valLostDays * 200000) / valTotalHours;
var roundedRate = severityRate.toFixed(2);
var interpretation = "";
if (severityRate === 0) {
interpretation = "Excellent! No lost workdays recorded.";
} else if (severityRate > 50) {
interpretation = "This is a high severity rate. Reviewing safety protocols is highly recommended.";
}
resultDisplay.innerHTML = "Severity Rate: " + roundedRate + "" + interpretation;
}