Workplace Injury Rate Calculation

Workplace Injury Rate Calculator (TRIR & DART)

Total hours worked by ALL employees in the period (usually 1 year).

Total number of OSHA recordable cases.

Cases involving Days Away, Restricted, or Transferred.

Calculation Results

TRIR (Total Recordable Incident Rate):

0.00

DART Rate:

0.00

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Understanding Workplace Injury Rate Calculations

In the field of occupational safety, tracking incident rates is critical for benchmarking your company's performance against industry standards and identifying areas for safety improvements. These rates are standardized by OSHA (Occupational Safety and Health Administration) to represent the number of injuries per 100 full-time employees.

What is TRIR?

The Total Recordable Incident Rate (TRIR) is a mathematical formula that reveals how many work-related injuries or illnesses occurred per 100 full-time workers over a one-year period. It is the most common metric used by companies to evaluate their safety culture.

What is the DART Rate?

The DART Rate stands for Days Away, Restricted, or Transferred. It specifically measures the number of recordable incidents that resulted in the employee being unable to perform their normal duties, whether they had to stay home, work in a restricted capacity, or be transferred to another job temporarily. A high DART rate often indicates more severe injuries occurring in the workplace.

The Formulas

Both calculations use a base of 200,000 hours, which represents 100 employees working 40 hours per week for 50 weeks a year.

• TRIR Formula: (Number of Injuries × 200,000) / Total Hours Worked
• DART Formula: (Number of DART Incidents × 200,000) / Total Hours Worked

Example Calculation

Suppose a medium-sized construction company has the following data for the calendar year:

• Total Employee Hours: 450,000 hours
• Recordable Incidents: 8
• DART Cases: 3

To find the TRIR: (8 × 200,000) / 450,000 = 3.55

To find the DART: (3 × 200,000) / 450,000 = 1.33

This means for every 100 workers, approximately 3.55 sustained recordable injuries, and 1.33 of those were severe enough to require time away or restricted duty.

Why Do These Rates Matter?

1. OSHA Compliance: Companies in high-risk industries must report these numbers annually.
2. Insurance Premiums: Lower injury rates can lead to lower Workers' Compensation insurance costs.
3. Contract Bidding: Many prime contractors or government agencies require subcontractors to have a TRIR below a certain threshold (often below 3.0) to even bid on a project.
4. Safety Analysis: Trends in these numbers help safety managers determine if new training or equipment is working effectively.

function calculateInjuryRates() { var hours = parseFloat(document.getElementById('totalHours').value); var incidents = parseFloat(document.getElementById('recordableIncidents').value); var dart = parseFloat(document.getElementById('dartIncidents').value); var resultsArea = document.getElementById('resultsArea'); var trirDisplay = document.getElementById('trirResult'); var dartDisplay = document.getElementById('dartResult'); var summaryText = document.getElementById('summaryText'); if (isNaN(hours) || hours incidents) { alert("DART cases cannot be higher than total recordable incidents, as DART is a subset of recordable cases."); return; } // Calculation: (Count * 200,000) / Total Hours var trir = (incidents * 200000) / hours; var dartRate = (dart * 200000) / hours; trirDisplay.innerHTML = trir.toFixed(2); dartDisplay.innerHTML = dartRate.toFixed(2); resultsArea.style.display = 'block'; var message = "Your company's TRIR of " + trir.toFixed(2) + " means that for every 100 full-time employees, approximately " + trir.toFixed(2) + " recordable injuries occurred over the course of a year. "; if (trir > 3.0) { message += "This rate may be considered high depending on your specific industry average."; } else { message += "This is generally considered a strong safety performance metric."; } summaryText.innerHTML = message; // Scroll to results resultsArea.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }