Wafer capacity converter (8-inch and 12-inch equivalent)
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KEY POINTS
Capacity in "8-inch equivalent" or "12-inch equivalent" is normalized by wafer area: one 12-inch (300 mm) wafer equals 2.25 wafers of 8 inches (200 mm). For example, 55,000 12-inch wafers per month is about 124,000 per month in 8-inch equivalent. Capacity counts wafer starts, though, and leading-edge nodes have many more steps per wafer, so the tools needed for the same wafer count differ greatly.
Capacity
"8-inch equivalent" and "12-inch equivalent" follow the convention of normalizing by wafer area (one 300 mm wafer = 2.25 wafers of 200 mm; one 200 mm wafer = about 1.78 wafers of 150 mm). Fab capacity is normally quoted as wafer starts, not as shipped good chips.
Converted to good chips
Calculated with a 0.1 mm scribe width and 3 mm edge exclusion. Use the die per wafer calculator to change these conditions.
Conversion factors by diameter
| From | → 6-inch equivalent | → 8-inch equivalent | → 12-inch equivalent |
|---|---|---|---|
| 150 mm | ×1 | ×0.563 | ×0.250 |
| 200 mm | ×1.778 | ×1 | ×0.444 |
| 300 mm | ×4.000 | ×2.250 | ×1 |
Reading capacity figures
News about new or expanded fabs states capacity with a diameter and period, such as "50,000 wafers per month (12-inch equivalent)." Converting by area makes it possible to add up or compare fabs with different wafer sizes. A 300 mm wafer has 2.25 times the area of a 200 mm wafer, so the same number of wafers yields roughly 2.25 times as many chips (slightly more in practice, because edge loss is a smaller share).
Area conversion assumes the same product, however. Leading-edge logic has many more lithography steps and each wafer takes longer to process, so the same monthly wafer count needs far more tools and cleanroom space than a mature node. Capacity comparisons need to look at the node and product type along with the wafer count.
FAQ
How do I convert 12-inch wafers to 8-inch equivalent?
Multiply by (300/200)² = 2.25. One 8-inch wafer is about 1.78 wafers of 6 inches.
Does capacity mean shipped chips?
No. Fab capacity is normally quoted as wafer starts. Good chips depend on dies per wafer and yield.
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Last updated: October 23, 2026