function calculateRepairMetrics() {
// 1. Get input values
var totalUnitsInput = document.getElementById("totalUnits").value;
var failedUnitsInput = document.getElementById("failedUnits").value;
var avgCostInput = document.getElementById("avgCost").value;
var errorDiv = document.getElementById("errorMessage");
var resultsDiv = document.getElementById("resultsArea");
// 2. Validate inputs
if (totalUnitsInput === "" || failedUnitsInput === "") {
errorDiv.style.display = "block";
errorDiv.innerText = "Please enter both Total Units and Repaired Units.";
resultsDiv.style.display = "none";
return;
}
var total = parseFloat(totalUnitsInput);
var failed = parseFloat(failedUnitsInput);
var costPer = parseFloat(avgCostInput);
// Handle optional cost
if (isNaN(costPer)) {
costPer = 0;
}
// 3. Logic Validation
if (total <= 0) {
errorDiv.style.display = "block";
errorDiv.innerText = "Total units must be greater than zero.";
resultsDiv.style.display = "none";
return;
}
if (failed total) {
errorDiv.style.display = "block";
errorDiv.innerText = "Repaired units cannot be negative or exceed total units.";
resultsDiv.style.display = "none";
return;
}
// 4. Clear errors
errorDiv.style.display = "none";
// 5. Calculations
var repairRate = (failed / total) * 100;
var reliabilityRate = 100 – repairRate;
var dpmo = (failed / total) * 1000000;
var totalCost = failed * costPer;
// 6. Update DOM
document.getElementById("displayRate").innerText = repairRate.toFixed(2) + "%";
document.getElementById("displayReliability").innerText = reliabilityRate.toFixed(2) + "%";
document.getElementById("displayDPMO").innerText = Math.round(dpmo).toLocaleString();
document.getElementById("displayTotalCost").innerText = "$" + totalCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
// 7. Show results
resultsDiv.style.display = "block";
}
Understanding Repair Rate Calculations
The repair rate is a critical Key Performance Indicator (KPI) in manufacturing, quality control, and asset management. It measures the frequency at which products require corrective maintenance relative to the total number of units produced or deployed. Accurate calculation of this metric allows businesses to identify quality drift, assess warranty liabilities, and improve overall product reliability.
Why Calculate Repair Rate?
Monitoring the repair rate provides immediate feedback on the health of your production line or the durability of your inventory. A high repair rate typically indicates defects in materials, assembly errors, or design flaws. Conversely, a low repair rate (and consequently a high reliability rate) is a strong indicator of effective Quality Assurance (QA) processes.
Key Benefit: Reducing your repair rate by just 1% can lead to significant savings in labor, shipping, and replacement parts, directly boosting the bottom line.
The Repair Rate Formula
The fundamental formula for calculating the repair rate is a simple ratio expressed as a percentage:
Repair Rate (%) = (Number of Repaired Units / Total Units) × 100
For example, if you manufacture 5,000 widgets and 150 are returned for repairs:
Total Units = 5,000
Repaired Units = 150
Calculation: (150 / 5,000) = 0.03
Result: 3.00% Repair Rate
Related Metrics Explained
Our calculator provides three distinct metrics to give a holistic view of your quality control status:
Repair Rate (Failure Rate): The percentage of your inventory that failed performance standards and required intervention.
Reliability Rate: The inverse of the repair rate. This represents the percentage of units that performed without issue. In Six Sigma methodologies, this is often referred to as First Pass Yield (FPY) if calculated at the end of the production line.
DPMO (Defects Per Million Opportunities): A standard Six Sigma metric that extrapolates your current failure rate to a scale of one million units. This is useful for comparing quality performance across different production volumes or industries.
Impact of Repair Costs
While the percentage tells you how often things break, the Total Quality Cost tells you how much it hurts your budget. By inputting the "Average Cost Per Repair," you can quantify the financial impact of defects. This cost should include:
Technician labor hours
Replacement parts and consumables
Shipping and logistics for returns
Administrative overhead
Improving Your Repair Rate
To lower this metric, focus on Root Cause Analysis (RCA). Track why units are being repaired—is it a specific component failure, software bug, or user error? Categorizing repairs allows you to apply Pareto analysis (the 80/20 rule) to fix the small number of defects causing the majority of your repairs.