The OSHA Lost Time Incident Rate (LTIR) is a crucial metric used in workplace safety to quantify the frequency of work-related injuries and illnesses that result in an employee being unable to perform their regular job duties or missing at least one scheduled workday. This rate helps organizations benchmark their safety performance against industry averages and track trends over time. A lower LTIR generally indicates a safer working environment.
The formula for calculating the Lost Time Incident Rate is:
LTIR = (Number of Recordable Incidents Causing Lost Time × 200,000) / Total Hours Worked
The 200,000 multiplier represents the number of hours that 100 employees working 40 hours per week for 50 weeks per year would accumulate (100 employees * 40 hours/week * 50 weeks/year = 200,000 hours). This standardizes the rate to allow for comparison across businesses of different sizes and with varying total employee hours.
Key Components:
Number of Recordable Incidents Causing Lost Time: This is the total count of injuries or illnesses that required medical treatment beyond first aid and resulted in lost workdays.
Total Hours Worked: This is the aggregate number of hours worked by all employees during the specified period. It should include overtime hours.
Time Period Covered (in Days): While the primary formula uses total hours, sometimes the calculation is performed over a specific duration (like a year). For this calculator, we focus on the direct total hours worked and the number of lost-time incidents within that timeframe. The "Time Period Covered (in Days)" input is often used in conjunction with calculating total hours if not directly provided, but for this calculator's core function, we are using the provided total hours directly.
A lower LTIR signifies better safety practices and a more secure workplace for employees. Organizations should aim to continuously reduce this rate through proactive safety measures, training, and incident investigation.
function calculateLTIR() {
var totalHoursWorked = parseFloat(document.getElementById("totalHoursWorked").value);
var recordableIncidents = parseFloat(document.getElementById("recordableIncidents").value);
var timePeriodDays = parseFloat(document.getElementById("timePeriodDays").value); // This is included as per the prompt but not directly used in the core LTIR formula if totalHoursWorked is provided. It might be for context or a slightly different calculation variant. For the standard LTIR, totalHoursWorked is the primary driver.
var resultElement = document.getElementById("result");
resultElement.innerHTML = ""; // Clear previous results
// Validate inputs
if (isNaN(totalHoursWorked) || totalHoursWorked <= 0) {
resultElement.innerHTML = "Please enter a valid number for Total Hours Worked greater than zero.";
return;
}
if (isNaN(recordableIncidents) || recordableIncidents < 0) {
resultElement.innerHTML = "Please enter a valid number for Recordable Incidents (cannot be negative).";
return;
}
if (isNaN(timePeriodDays) || timePeriodDays <= 0) {
resultElement.innerHTML = "Please enter a valid number for Time Period Covered (in Days) greater than zero.";
return;
}
// Calculate LTIR
var ltir = (recordableIncidents * 200000) / totalHoursWorked;
// Display result
resultElement.innerHTML =
"Your calculated Lost Time Incident Rate (LTIR) is: " +
ltir.toFixed(2) + " per 200,000 hours worked.";
}
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