How to Calculate Rejection Rate

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Rejection Rate Calculator

Please enter valid positive numbers. Rejections cannot exceed total production.
Rejection Rate
0.00%
Acceptance Rate (Yield)
100.00%
Parts Per Million (PPM) Defective
0

How to Calculate Rejection Rate

In manufacturing, quality assurance, and data entry processes, the Rejection Rate is a critical Key Performance Indicator (KPI). It measures the percentage of products, parts, or applications that fail to meet quality standards and are discarded or returned for rework. Keeping this rate low is essential for minimizing waste and maximizing profitability.

The Rejection Rate Formula

The calculation is straightforward. It compares the number of defective items to the total number of items processed.

Rejection Rate = (Total Rejected Items / Total Items Produced) × 100

Example Calculation

Imagine a factory production line produces 5,000 widgets in a single shift. During quality control inspection, 125 widgets are found to have defects and are rejected.

  • Total Produced: 5,000
  • Total Rejected: 125
  • Calculation: (125 / 5,000) = 0.025
  • Percentage: 0.025 × 100 = 2.5% Rejection Rate

Why Monitoring Rejection Rate Matters

High rejection rates indicate inefficiencies in the production process. They can lead to:

  • Increased Costs: Wasted raw materials and labor.
  • Delayed Shipments: Reworking defective items takes time.
  • Equipment Issues: A sudden spike in rejections often signals machine failure or calibration issues.

Related Metrics: Acceptance Rate & PPM

This calculator also provides two other vital metrics:

  1. Acceptance Rate (Yield): The inverse of the rejection rate. If your rejection rate is 2.5%, your acceptance rate is 97.5%. This represents the percentage of sellable goods.
  2. PPM (Parts Per Million): In high-volume manufacturing (like Six Sigma methodologies), percentages are often too broad. PPM standardizes the defect rate to one million units, allowing for more precise benchmarking.

How to Reduce Your Rejection Rate

To lower this metric, consider implementing regular machinery maintenance, improving raw material quality checks, and providing better training for operators. Continuous monitoring using a calculator like this helps identify trends before they become expensive problems.

function calculateRejectionRate() { // Get input elements var totalInput = document.getElementById('totalProduced'); var rejectedInput = document.getElementById('totalRejected'); var errorMsg = document.getElementById('rr-error-msg'); // Get output elements var resultRejection = document.getElementById('result-rejection-rate'); var resultAcceptance = document.getElementById('result-acceptance-rate'); var resultPPM = document.getElementById('result-ppm'); // Parse values var total = parseFloat(totalInput.value); var rejected = parseFloat(rejectedInput.value); // Validation Logic if (isNaN(total) || isNaN(rejected)) { errorMsg.style.display = 'block'; errorMsg.innerText = "Please enter valid numbers in both fields."; return; } if (total <= 0) { errorMsg.style.display = 'block'; errorMsg.innerText = "Total produced must be greater than zero."; return; } if (rejected total) { errorMsg.style.display = 'block'; errorMsg.innerText = "Rejected items cannot exceed total produced."; return; } // Hide error message if valid errorMsg.style.display = 'none'; // Calculations var rejectionRate = (rejected / total) * 100; var acceptanceRate = 100 – rejectionRate; var ppm = (rejected / total) * 1000000; // Display Results resultRejection.innerText = rejectionRate.toFixed(2) + "%"; resultAcceptance.innerText = acceptanceRate.toFixed(2) + "%"; // Format PPM with commas for readability resultPPM.innerText = Math.round(ppm).toLocaleString(); }

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