About the Manufacturing Yield Calculator
This manufacturing yield calculator measures how well a multi-step process turns input into good output. For each process step, enter the units that went in, the units that passed first time without rework, and the units scrapped. It returns the first pass yield (FPY) of every step, the rolled throughput yield (RTY) of the whole line, the final (traditional) yield, scrap rate and the amount of rework hiding in the process.
It is built for production supervisors, quality and process engineers, lean and Six Sigma practitioners and plant managers. Final yield only counts what is thrown away, so a line that reworks a lot can look excellent on that measure. Rolled throughput yield multiplies the first-pass yields of every step and shows the probability that a unit gets through the entire process right the first time — the “hidden factory” of rework becomes visible.
Units that are neither passed first time nor scrapped are treated as reworked and passed on. Enter each step’s actual units in; normally that is the previous step’s input minus its scrap, but you can enter your own figures if parts are added or pulled for testing between steps.
With the default inputs, the rolled throughput yield (rty) is 88.35%. Change any value above to recalculate instantly.
How to use the manufacturing yield calculator
- 1List your process steps in order, one per line.
- 2For each, enter units in, units passed first time and units scrapped.
- 3Read the rolled throughput yield and compare it with final yield.
- 4Use the chart and table to find the step with the lowest first pass yield.
- 5Target that step first — it raises RTY and cuts rework the most.
Formula and method
First pass yield for a step is the share of units that pass without any rework or scrap. Rolled throughput yield multiplies the first pass yields of all steps, giving the probability that a unit passes every step defect-free the first time. Because it multiplies, a line of several 95% steps quickly drops toward 80%.
Final (traditional) yield divides the good units leaving the last step — its input minus its scrap — by the units that entered the first step, so it counts reworked units as good. Scrap rate is total scrap divided by starting units. Rework at each step is units in minus units passed first time minus units scrapped.
- FPY_i
- First pass yield of step i
- RTY
- Rolled throughput yield of the whole process
- n
- Number of process steps
Worked examples
Four-step fabrication line
Step FPYs are 97.0%, 94.95%, 97.44% and 98.45%. Multiplying them gives an RTY of 88.35%. The line ships 962 good units from 1,000 started — a 96.2% final yield — because 82 units were quietly reworked and only 38 scrapped.
Three steps at 95% each with no scrap
Every unit is eventually saved, so final yield is 100%. But each step reworks 5% of units, and 0.95³ = 85.74% RTY: about one unit in seven needs rework somewhere along the line.
PCB assembly with heavy scrap at test
FPYs are 97.0%, 98.48% and 92.39%, giving 88.26% RTY. 2,000 boards start and 1,880 pass the final step, a 94% final yield with 120 boards (6%) scrapped — mostly at functional test, which is where improvement effort should go.
Frequently asked questions
What is first pass yield?+
First pass yield (FPY), also called first time yield, is the percentage of units that complete a process step correctly the first time, without rework or scrap. If 1,000 units enter and 970 pass straight through, FPY is 97%.
How do you calculate rolled throughput yield?+
Multiply the first pass yields of every step in the process. Four steps with FPYs of 97%, 95%, 97.4% and 98.5% give 0.97 × 0.95 × 0.974 × 0.985 ≈ 88.4% RTY — the chance a unit gets through the whole line with no defects.
What is the difference between final yield and rolled throughput yield?+
Final yield counts reworked units as good and only penalises scrap, so it can look high even when lots of rework is happening. RTY counts any rework or scrap at any step as a failure, so it exposes the hidden cost of rework.
What is a good first pass yield?+
It depends heavily on the industry and product complexity. Mature high-volume processes often run above 95–99% per step, while new products or complex assemblies may be lower. Track FPY by step over time and focus on the lowest one.
How is scrap rate calculated?+
Scrap rate is the number of units scrapped divided by the number of units started (or produced), times 100. 38 scrapped units from 1,000 started is a 3.8% scrap rate. Some plants measure scrap by weight or cost instead of units.