A professional tool to calculate weighted defects, analyze quality metrics, and determine Weighted Defects Per Unit (WDPU) for manufacturing and software quality assurance.
Production Data
The total number of items tested in this batch.
Please enter a valid number greater than 0.
Defect Categories & Weights
Severe defects that render the unit unusable or unsafe.
Standard weight is often 10.
Defects that likely result in failure or material reduction in usability.
Standard weight is often 3 or 5.
Cosmetic flaws or minor deviations from standards.
Standard weight is usually 1.
Total Weighted Defect Score
140
Sum of all defects multiplied by their weights
WDPU (Weighted Defects Per Unit)
0.140
Total Defect Count
62
Average Weight
2.26
Defect Contribution Breakdown
Detailed Calculation Table
Category
Count
Weight
Weighted Score
What is Calculate Weighted Defects?
To calculate weighted defects is to apply a statistical quality control method that assigns varying degrees of severity to different types of defects found during inspection. In manufacturing, software development, and service industries, not all errors are created equal. A minor cosmetic scratch does not have the same financial or functional impact as a critical safety failure.
By using a weighted system, quality assurance (QA) managers can derive a more accurate representation of product quality than a simple defect count would provide. This method transforms raw defect data into actionable business intelligence, allowing organizations to prioritize fixes, assess vendor performance, and determine if a production batch meets the Acceptable Quality Level (AQL).
This metric is widely used by production managers, Six Sigma practitioners, and supply chain auditors who need to calculate weighted defects to maintain high standards and minimize the Cost of Poor Quality (COPQ).
Calculate Weighted Defects Formula and Explanation
The mathematical foundation used to calculate weighted defects is a weighted sum. It involves categorizing defects into severity classes (typically Critical, Major, and Minor), assigning a numerical weight to each class, and summing the products of the counts and weights.
WDPU: 300 / 500 = 0.60. This high WDPU suggests a systemic issue in the sewing process, likely requiring machine calibration.
How to Use This Calculator
Follow these steps to accurately calculate weighted defects for your production line:
Enter Total Units: Input the total number of items in the batch being inspected.
Input Defect Counts: Enter the raw number of Critical, Major, and Minor defects found.
Adjust Weights: The calculator defaults to standard weights (10, 5, 1). Adjust these if your specific industry standard (e.g., automotive vs. textile) requires different severity weighting.
Analyze Results: Review the Total Weighted Score and WDPU. Use the chart to see which defect category is contributing most to your quality score.
Copy & Report: Use the "Copy Results" button to paste the data directly into your QA reports or emails.
Key Factors That Affect Results
When you calculate weighted defects, several external factors influence the outcome and its financial interpretation:
Severity Definitions: The subjectivity in defining what constitutes a "Major" vs. "Minor" defect can skew results. Clear operational definitions are required.
Weighting Scales: Using a 10-5-1 scale vs. a 100-50-10 scale changes the raw score magnitude, though relative ratios may remain similar.
Sample Size: Calculating based on a small sample size (e.g., 5 units) yields high margin of error compared to 100% inspection or statistically significant sampling (ANSI/ASQ Z1.4).
Inspector Fatigue: Human inspectors may miss minor defects late in a shift, artificially lowering the weighted score.
Complexity of Product: Complex products naturally have more opportunities for error. Comparing WDPU between a screw and a car engine is not valid.
Production Volume: High-speed production lines may tolerate higher absolute defect counts but require a very low WDPU to remain profitable.
Frequently Asked Questions (FAQ)
What is a standard "passing" score for weighted defects?
There is no universal passing score. It depends on the industry. Medical devices often require a WDPU near zero, whereas cheap novelty toys might tolerate a higher WDPU. Companies usually set an internal benchmark based on historical data.
Why use weights instead of just counting total defects?
Counting total defects treats a life-threatening failure the same as a cosmetic blemish. Weights reflect the true risk and cost associated with the defect, providing a more realistic view of quality health.
Can I change the weight values in the calculator?
Yes. The fields for weights are editable. Common alternative scales include 4-2-1 or 50-10-1 depending on the methodology (e.g., GCA score vs. standard AQL).
How does this relate to Six Sigma?
When you calculate weighted defects, you are generating data that feeds into Six Sigma metrics like DPMO (Defects Per Million Opportunities) and Sigma Level. It is a fundamental data collection step.
What is the difference between Defect and Defective?
A "defect" is a specific flaw. A "defective" is a unit that has one or more defects. This calculator focuses on defect counts, which is often more useful for root cause analysis.
Does this calculator handle financial loss?
Directly, no. However, you can assign dollar values as weights (e.g., cost to rework) to estimate the financial impact of the defects found in the batch.
What happens if I have 0 units inspected?
The calculator requires at least 1 unit to avoid division by zero errors when calculating WDPU. The input validation prevents entering 0 or negative numbers.
Is WDPU the same as DPU?
DPU (Defects Per Unit) counts all defects equally (Total Defects / Units). WDPU (Weighted Defects Per Unit) accounts for severity (Total Weighted Score / Units). WDPU is a more nuanced metric.
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units: document.getElementById('unitsInspected'),
cCount: document.getElementById('criticalCount'),
cWeight: document.getElementById('criticalWeight'),
mCount: document.getElementById('majorCount'),
mWeight: document.getElementById('majorWeight'),
nCount: document.getElementById('minorCount'),
nWeight: document.getElementById('minorWeight')
};
var results = {
totalScore: document.getElementById('totalScoreResult'),
wdpu: document.getElementById('wdpuResult'),
totalCount: document.getElementById('totalCountResult'),
avgWeight: document.getElementById('avgWeightResult'),
unitsError: document.getElementById('unitsError'),
tableBody: document.querySelector('#breakdownTable tbody')
};
function calculateResults() {
var units = parseFloat(inputs.units.value);
var cCount = parseFloat(inputs.cCount.value) || 0;
var cWeight = parseFloat(inputs.cWeight.value) || 0;
var mCount = parseFloat(inputs.mCount.value) || 0;
var mWeight = parseFloat(inputs.mWeight.value) || 0;
var nCount = parseFloat(inputs.nCount.value) || 0;
var nWeight = parseFloat(inputs.nWeight.value) || 0;
// Validation
if (isNaN(units) || units 0) {
avgWeight = totalWeightedScore / totalDefectCount;
}
// Update UI
results.totalScore.textContent = totalWeightedScore.toLocaleString();
results.wdpu.textContent = wdpu.toFixed(3);
results.totalCount.textContent = totalDefectCount.toLocaleString();
results.avgWeight.textContent = avgWeight.toFixed(2);
// Update Table
updateTable(cCount, cWeight, cScore, mCount, mWeight, mScore, nCount, nWeight, nScore);
// Update Chart
drawChart(cScore, mScore, nScore);
}
function updateTable(cc, cw, cs, mc, mw, ms, nc, nw, ns) {
var html = ";
// Helper to create row
function createRow(cat, count, weight, score, color) {
return '
' +
'
' + cat + '
' +
'
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'
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' +
'
' + score + '
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'
';
}
html += createRow('Critical', cc, cw, cs, '#dc3545'); // Red
html += createRow('Major', mc, mw, ms, '#fd7e14'); // Orange
html += createRow('Minor', nc, nw, ns, '#28a745'); // Green
// Total Row
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'
Total
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'
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–
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'
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results.tableBody.innerHTML = html;
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ctx.clearRect(0, 0, width, height);
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ctx.arc(centerX, centerY, radius, 0, 2 * Math.PI);
ctx.fill();
ctx.fillStyle = '#666′;
ctx.font = '16px Arial';
ctx.textAlign = 'center';
ctx.fillText('No weighted defects', centerX, centerY);
return;
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var startAngle = 0;
// Data array: value, color, label
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{ val: cScore, col: '#dc3545', label: 'Critical' },
{ val: mScore, col: '#fd7e14', label: 'Major' },
{ val: nScore, col: '#28a745', label: 'Minor' }
];
// Draw Pie
for (var i = 0; i 0) {
var sliceAngle = (data[i].val / total) * 2 * Math.PI;
var endAngle = startAngle + sliceAngle;
ctx.beginPath();
ctx.moveTo(centerX, centerY);
ctx.arc(centerX, centerY, radius, startAngle, endAngle);
ctx.closePath();
ctx.fillStyle = data[i].col;
ctx.fill();
startAngle = endAngle;
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}
// Draw Legend via JS (Simulating)
var legendHtml = ";
for (var i = 0; i < data.length; i++) {
var pct = ((data[i].val / total) * 100).toFixed(1);
legendHtml += '' +
'■ ' + data[i].label + ' (' + pct + '%)';
}
document.getElementById('chartLegend').innerHTML = legendHtml;
}
function resetCalculator() {
inputs.units.value = 1000;
inputs.cCount.value = 2;
inputs.cWeight.value = 10;
inputs.mCount.value = 15;
inputs.mWeight.value = 5;
inputs.nCount.value = 45;
inputs.nWeight.value = 1;
calculateResults();
}
function copyResults() {
var text = "Weighted Defects Calculation Results:\n";
text += "——————————–\n";
text += "Total Units Inspected: " + inputs.units.value + "\n";
text += "Total Weighted Score: " + results.totalScore.textContent + "\n";
text += "WDPU: " + results.wdpu.textContent + "\n";
text += "Total Defect Count: " + results.totalCount.textContent + "\n";
text += "——————————–\n";
text += "Breakdown:\n";
text += "Critical: " + inputs.cCount.value + " (Wt: " + inputs.cWeight.value + ")\n";
text += "Major: " + inputs.mCount.value + " (Wt: " + inputs.mWeight.value + ")\n";
text += "Minor: " + inputs.nCount.value + " (Wt: " + inputs.nWeight.value + ")\n";
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tempInput.select();
document.execCommand("copy");
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btn.textContent = "Copied!";
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