Per 1,000,000 Hours (International Standard)
Per 200,000 Hours (OSHA Standard)
Frequency Rate (LTIFR)
0.00
Understanding Frequency Rate Calculation in Safety
The Frequency Rate, often referred to as the Lost Time Injury Frequency Rate (LTIFR), is a crucial Key Performance Indicator (KPI) used in occupational health and safety. It quantifies the number of lost-time injuries occurring in a workplace relative to the total number of hours worked by all employees.
Unlike simply counting the number of accidents, the frequency rate allows companies to compare safety performance normalized against the size of the workforce and the duration of exposure to risk. This makes it possible to compare a small company's safety record with that of a large multinational corporation.
The Frequency Rate Formula
The calculation relies on three main components: the number of incidents, the total hours worked, and a multiplication factor used to standardize the result.
Frequency Rate = (Number of Lost Time Injuries × Multiplication Factor) / Total Man-Hours Worked
Which Multiplication Factor Should You Use?
There are two common standards used globally:
1,000,000 (International Standard): Many countries and industries (including Australia and parts of Europe) use one million hours as the base. This represents roughly 500 full-time employees working for one year.
200,000 (OSHA Standard): The Occupational Safety and Health Administration (USA) uses 200,000 hours. This represents 100 full-time employees working 40 hours a week for 50 weeks a year.
How to Calculate Total Man-Hours
To ensure accuracy, "Total Man-Hours" should include the actual hours worked by all employees, including overtime and contract labor if applicable. It should exclude:
Paid leave (vacation, sick leave)
Public holidays
Lunch breaks (unless paid and worked)
Example Calculation
Let's assume a manufacturing plant has the following data for the year:
Number of Injuries: 3 Lost Time Injuries
Total Employees: 250
Total Hours Worked: 500,000 hours
Using the 1,000,000 factor:
Calculation: (3 × 1,000,000) / 500,000 = 6.0
This means that for every million hours worked, there are 6 lost time injuries.
Why is LTIFR Important?
Monitoring the Frequency Rate allows safety managers to:
Identify trends in safety performance over time.
Benchmark against industry averages.
Determine the effectiveness of new safety protocols.
Fulfil regulatory reporting requirements.
However, it is a "lagging indicator," meaning it measures past events. It should ideally be used in conjunction with "leading indicators" (like near-miss reporting and safety audits) to create a proactive safety culture.
function calculateFrequencyRate() {
// Get input values
var injuriesInput = document.getElementById('numInjuries');
var hoursInput = document.getElementById('totalHours');
var standardInput = document.getElementById('calcStandard');
var resultBox = document.getElementById('resultBox');
var resultValue = document.getElementById('resultValue');
var resultText = document.getElementById('resultText');
var hoursError = document.getElementById('hoursError');
// Parse values
var injuries = parseFloat(injuriesInput.value);
var hours = parseFloat(hoursInput.value);
var factor = parseFloat(standardInput.value);
// Validation
var isValid = true;
if (isNaN(hours) || hours <= 0) {
hoursError.style.display = 'block';
isValid = false;
} else {
hoursError.style.display = 'none';
}
if (isNaN(injuries) || injuries < 0) {
isValid = false;
}
if (!isValid) {
resultBox.style.display = 'none';
return;
}
// Calculation Logic
// Formula: (Injuries * Factor) / Hours
var frequencyRate = (injuries * factor) / hours;
// Display Result
resultBox.style.display = 'block';
// Format to 2 decimal places
resultValue.innerHTML = frequencyRate.toFixed(2);
// Generate dynamic explanation based on the factor used
var standardName = (factor === 1000000) ? "1,000,000 hours" : "200,000 hours";
var interpretation = "This score indicates that for every " + standardName + " worked, there are " + frequencyRate.toFixed(2) + " lost time injuries.";
// Add a simple context note (Note: This is generic; specific thresholds depend on industry)
if (frequencyRate === 0) {
interpretation += "Excellent: You have zero recorded lost time injuries for this period.";
} else {
interpretation += "Compare this figure against your industry average to determine if your safety performance is improving or declining.";
}
resultText.innerHTML = interpretation;
}