Scrap Rate Calculation Formula

Scrap Rate Calculator

Analysis Results

Scrap Rate: 0%

Total Financial Loss: $0.00

Yield Rate: 0%

function calculateScrapRate() { var total = parseFloat(document.getElementById("totalProduced").value); var scrap = parseFloat(document.getElementById("scrapUnits").value); var unitCost = parseFloat(document.getElementById("costPerUnit").value) || 0; var resultDiv = document.getElementById("scrapResult"); if (isNaN(total) || isNaN(scrap) || total total) { alert("Scrap units cannot exceed total units produced."); return; } var scrapRate = (scrap / total) * 100; var totalLoss = scrap * unitCost; var yieldRate = 100 – scrapRate; document.getElementById("rateOutput").innerText = scrapRate.toFixed(2); document.getElementById("costOutput").innerText = "$" + totalLoss.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById("yieldOutput").innerText = yieldRate.toFixed(2); resultDiv.style.display = "block"; }

In manufacturing and production management, the scrap rate is a critical Key Performance Indicator (KPI) that measures the efficiency of a production process. It identifies the percentage of raw materials or finished products that fail to meet quality standards and must be discarded or reworked.

The Basic Scrap Rate Formula

The standard formula for calculating the scrap rate is straightforward:

Scrap Rate = (Total Scrap Units / Total Units Produced) × 100

Example Calculation

Suppose a factory produces 10,000 smartphone screens in a single shift. During quality inspection, 250 screens are found to have cracks or pixel defects and are sent to the scrap bin.

• Total Produced: 10,000
• Scrap Units: 250
• Calculation: (250 / 10,000) × 100 = 2.5%

In this scenario, the scrap rate is 2.5%, meaning the production yield is 97.5%.

Why Calculating Scrap Rate Matters

Monitoring your scrap rate is not just about counting waste; it's about identifying systemic issues in your manufacturing pipeline. High scrap rates typically indicate:

1. Machine Malfunction: Equipment that isn't calibrated correctly may produce consistent defects.
2. Substandard Raw Materials: Poor quality inputs often lead to poor quality outputs.
3. Training Gaps: Human error is a significant contributor to scrap in manual assembly processes.
4. Financial Impact: Every scrap unit represents lost labor, energy, and material costs that cannot be recovered.

Scrap Rate vs. Yield Rate

While the scrap rate focuses on what was lost, the Yield Rate focuses on what was successful. They are two sides of the same coin. If your scrap rate is 4%, your yield rate is 96%. Lean manufacturing processes aim to drive the scrap rate as close to 0% as possible (often referred to as "Zero Defects" or "Six Sigma" quality levels).

Strategies to Reduce Scrap

To improve your production efficiency, consider the following steps:

• Preventative Maintenance: Regularly service machinery to prevent "drift" in precision.
• Employee Training: Ensure operators are fully trained on quality standards.
• Real-time Monitoring: Use sensors and IoT devices to catch defects the moment they occur rather than at the end of the line.
• Vendor Audits: Regularly check your suppliers to ensure raw material consistency.