TAHA Engineering Toolsby TAHA Knowledge Lab

Industrial & Manufacturing

Scrap Rate, Yield & First Pass Yield Calculator

Scrap rate, yield, rework rate and first pass yield of a process.

Inputs

Used to estimate the cost of scrap. Leave empty if not needed.

Result

First pass yield (FPY)
92%
Final yield (good output)
97%
Scrap rate
3%
Rework rate
5%
Good units
970units

Only 92% of units were right first time. Final yield is 97% because reworked units were recovered, but rework still costs time and money.

  • Enter a cost per unit to see the cost of scrap.

Educational estimate — check the assumptions below.

About this calculator

Final yield shows how much good product comes out of a process. It hides the cost of rework, because reworked parts end up counted as good. First pass yield (FPY) shows the share of units that were right the first time, with no scrap and no rework. It is a better measure of how well the process really runs.

Formula

  • Scrap rate = Scrapped ÷ Started
  • Final yield = (Started − Scrapped) ÷ Started
  • Rework rate = Reworked ÷ Started
  • First pass yield = (Started − Scrapped − Reworked) ÷ Started
  • Cost of scrap = Scrapped × cost per unit

Worked example

1000 units started, 30 scrapped, 50 reworked and then passed:

  • Scrap rate = 30 ÷ 1000 = 3%
  • Final yield = 970 ÷ 1000 = 97%
  • First pass yield = (1000 − 30 − 50) ÷ 1000 = 92%

For a process with several steps, multiply the FPY of each step to get the rolled throughput yield: 95% × 98% × 92% = 85.7%.

Assumptions and limitations

  • All counts refer to the same batch or period.
  • Units that are reworked more than once are counted once.
  • Cost of scrap uses only the cost you enter; disposal, delays and lost capacity are extra.

References

  • Standard quality metrics used in lean and Six Sigma practice.