Variables
Description
What is this formula?
Scrap Rate measures the percentage of manufactured units that must be discarded because they fail to meet quality requirements and cannot be economically reworked. It is a key manufacturing metric used to quantify waste and process inefficiency.
When to use it
Use this formula when monitoring production quality, evaluating process efficiency, identifying waste sources, calculating manufacturing losses, or supporting continuous improvement programs.
Example
A factory produces 12,000 parts during a production run. Inspection reveals that 360 parts are defective and must be scrapped.
Data:
T = 12,000 units
S = 360 units
Formula:
SR = (S / T) × 100
Substitution:
SR = (360 / 12,000) × 100
Result:
SR = 3 %
The manufacturing process has a scrap rate of 3%.
Applications
Quality management
Lean manufacturing
Waste reduction programs
Production cost analysis
Manufacturing process improvement
Note
The definition of scrap can vary between organizations. Some companies classify reworkable products separately, while others include certain repairable defects in scrap calculations. Consistent internal definitions are important when comparing scrap rates over time.