Scrap Rate Calculator

Calculate manufacturing scrap rate and yield. This practical tool is an engineering estimate—validate decisions against machine, material, mold, and process data.

Formula and method

Scrap rate = scrap ÷ (good + scrap) × 100.

Inputs and units

Enter measured or specified values in the displayed units. Keep units consistent; results are rounded for practical planning. This first release uses the displayed engineering units rather than a unit-switcher.

Worked example

300 scrap ÷ (9,700 good + 300 scrap) × 100 = 3%.

Use this with an explicit production count

Count good and scrap parts over the same time window and definition. The companion yield value is useful for material and output planning.

What changes the result most

How rework, startup waste, runner recovery, and customer rejects are classified.

Common mistake

Mixing cavity defects, startup purge, and recoverable runner material without a stated rule.

Interpretation, assumptions, and limitations

This tool provides an estimate for planning and education. It does not replace machine maker limits, material data sheets, mold trials, cavity-pressure data, process validation, or qualified engineering review.

FAQ

Can I use this as a final production setting?

No. Confirm with validated process data and the applicable machine and material documentation.

Why can the real result differ?

Geometry, melt behavior, pressure loss, material lot, temperature, cooling layout, and operating practice can materially affect results.