Die Yield And Cost Calculator: Who Benefits and Why
Reviewed by the OnlineFree.app team · Updated
Key points
- Cost per good die equals wafer cost divided by the number of dies that pass test.
- At 800 mm², 0.1 defects/cm², and $17,000 per wafer, the calculator shows about $607 per good die.
- Splitting the same 800 mm² into two 400 mm² chiplets lowers modeled silicon cost to about $366 per equivalent package.
- The 858 mm² reticle field is a hard lithography boundary; larger designs need stitching or chiplets.
- The chiplet comparison is a silicon-only sanity check, not a full packaging business case.
What does cost per good die actually mean?
Cost per good die is the processed wafer cost divided by the number of dies on that wafer that pass test. It is the cleanest single number for comparing silicon options because it combines area, defect density, and wafer price instead of treating yield as an afterthought.
The Die Yield And Cost Calculator applies the Murphy yield model, Y = ((1 − e^(−A·D0)) / (A·D0))², with area A in cm². As of 2026, the calculator uses a 300 mm wafer and estimates gross dies with the classic πR²/S − 2πR/√(2S) approximation, where R = 147 mm after 3 mm edge exclusion. Good dies are floor(gross dies × yield), and cost per good die is wafer cost ÷ good dies.
That matters because a wafer can look expensive per wafer and still be cheap per usable die. Conversely, a large die can turn a $17,000 wafer into a very expensive known-good part. For wafer background, see wafer (electronics)).
A concrete 800 mm² example
With the default inputs — 800 mm² die area, 0.1 defects/cm², and $17,000 per 300 mm wafer — the calculator predicts about 47.4% yield. It estimates 61 gross dies per wafer, 28 good dies, and $607 per good die. That is about $0.76 per mm² of good silicon.
Splitting the same 800 mm² into equal chiplets changes the arithmetic sharply. Two 400 mm² chiplets each yield about 67.9%; the calculator shows 93 good chiplets per wafer at about $183 each, or roughly $366 for the equivalent two-chiplet package. Four 200 mm² chiplets come to about $283, and eight 100 mm² chiplets to about $245.
We built that comparison into the Die Yield And Cost Calculator because the monolithic-versus-chiplet question is usually asked too late, after the floorplan is fixed. The numbers are silicon-only, so treat them as a first screen, not a procurement quote.
Where the reticle limit bites
The 26 × 33 mm reticle field is about 858 mm². That is a real boundary in lithography: a larger design needs stitching or a chiplet split. At 0.1 defects/cm², an 858 mm² die still yields roughly 45% in the calculator, producing about 56 gross dies and 25 good dies per wafer, or about $680 per good die.
Push the design to 3,000 mm² at the same defect density and the model turns brutal: yield falls to about 10%, gross dies per wafer to about 10, and good dies to roughly 1. Cost per good die jumps to about the full $17,000 wafer cost. That is the exponential penalty the Murphy model is there to expose.
The reticle limit is a standard lithography constraint, not a calculator artifact; see reticle for background. If a design is near or above that limit, the chiplet comparison is the more useful half of the page.
Who benefits from a die-yield cost model?
Semiconductor analysts get a fast sanity check before they repeat a supplier’s yield claim. Hardware product and packaging engineers can see whether a chiplet split is worth exploring before committing to an interposer and advanced package. Supply-chain and capacity planners can translate wafer starts into good die supply, and technically literate investors can test whether a large-die story holds together.
The common mistake is to use one defect density for every product. D0 varies by process, maturity, and design sensitivity. We advise running 0.05, 0.1, and 0.25 defects/cm² to see the range, then replacing those with measured foundry data when you have it. The tool’s default of 0.1 is a placeholder, not a forecast.
It also helps to compare cost per good mm², not just cost per die. A small die can have a low cost per die and a worse cost per mm². The Die Yield And Cost Calculator reports both so you can separate yield gains from area effects.
What the chiplet comparison leaves out
The chiplet side of the calculator holds total silicon area constant and scales the good-chiplet cost by the number needed. It does not add interposer cost, assembly yield, test cost, thermal constraints, or known-good-die screening. Those can easily dominate the silicon savings at 2.5D or 3D packaging.
It also ignores power, latency, and bandwidth trade-offs. A chiplet split that looks cheaper per good die can be the wrong product decision if the interconnect or package is too expensive. Use the comparison to size the silicon opportunity, then add packaging and system costs before you make a sourcing decision.
We keep the model deliberately transparent for that reason. It is a one-screen sanity check, not a sign-off tool. If the result matters commercially, verify the wafer cost, defect density, and packaging assumptions with your foundry and OSAT.
How do you sanity-check the result?
Start with the tool’s defaults, then change one input at a time. If defect density doubles from 0.1 to 0.2, yield on the 800 mm² die falls from about 47% to roughly 25%; the cost per good die rises accordingly. If wafer cost halves, cost per good die halves, but the chiplet ranking usually stays the same.
Check the gross-dies estimate against your own geometry for very small or very large die. The πR²/S − 2πR/√(2S) formula is an approximation; it does not model every edge exclusion or layout effect. For a 25 mm² die it will be close enough for planning, but for a 3,000 mm² design it is a coarse guide.
Finally, treat every number as an estimate. The calculator is free and requires no account, and it sits alongside other OnlineFree.app free online tools. Verify important figures before you put them in a business case, and do not enter confidential cost data you are not allowed to share.
Frequently asked questions
What does the Die Yield And Cost Calculator compute?
The Die Yield And Cost Calculator computes predicted die yield, gross and good dies per 300 mm wafer, cost per good die, and cost per mm² of good silicon from die area, defect density, and wafer cost. It also compares the same total area as one monolithic die or as 2, 4, or 8 equal chiplets.
Is the Die Yield And Cost Calculator free to use?
Yes. The Die Yield And Cost Calculator is a free, no-signup browser tool on OnlineFree.app. You enter area, defect density, and wafer cost, and the page returns the yield and cost figures immediately. Because wafer costs can be commercially sensitive, check the site’s privacy policy before entering confidential numbers.
Why can chiplets lower cost per good die?
Smaller die area improves yield under the Murphy model, so a wafer produces a higher fraction of good chiplets. In the default 800 mm² example, the calculator drops silicon cost per equivalent package from about $607 monolithic to about $366 with two chiplets. That comparison excludes packaging and assembly cost.
What defect density should I enter?
There is no universal D0. The calculator’s help text cites roughly 0.05–0.25 defects/cm² for mature leading-edge processes and defaults to 0.1. Use your foundry’s measured yield data or run a range of values to see sensitivity; the result is only as good as the D0 you supply.
Does the Die Yield And Cost Calculator include packaging cost?
No. The Die Yield And Cost Calculator reports silicon-only economics: wafer cost divided by good dies, plus the chiplet comparison using the same total silicon area. It does not include interposer, assembly, test, thermal, or known-good-die costs. For a full chiplet business case, add those separately and verify with suppliers.