Engineering tool
Stackup thickness calculator
Estimate the finished thickness of a 4 to 100 layer PCB from its copper weights and glass-style plies, and check the drilled-hole aspect ratio before you send the stackup out. The calculator opens with a 16-layer example (2-ply 2116 cores, 1-ply 1078 prepreg); change any layer and the result updates immediately.
Inputs
Changing a default resets every layer of that kind. Override individual layers in the table below. Up to 40 layers the example uses 2-ply 2116 cores and 1-ply 1078 prepreg; above 40 layers it switches to the thin construction typical of high-layer-count builds, 1-ply 1078 cores and 1-ply 1067 prepreg.
Result
Layer-by-layer stackup
An N-layer board has N copper layers and N − 1 dielectric layers, listed here top to bottom; outer dielectrics are prepreg (foil construction) and inner dielectrics alternate core and prepreg. Every row can be overridden.
| Layer | Type | Glass style / copper | Plies | Thickness (mm) |
|---|
Formula and assumptions
The calculator adds up every copper layer and every dielectric ply:
total = Σ copper(layer) + Σ plies(dielectric) × t(style) aspect ratio = total ÷ min finished holeCopper thickness per weight: 1/3 oz = 12 µm, 1/2 oz = 17 µm, 1 oz = 35 µm, 2 oz = 70 µm, 3 oz = 105 µm. Single-ply dielectric thickness t(style) is the typical pressed thickness at standard resin content from supplier construction tables (Resonac MCL, Isola 370HR, Panasonic MEGTRON 6): 1027 0.042 mm, 1037 0.050 mm, 1067 0.051 mm, 106 0.051 mm, 1078 0.072 mm, 1080 0.070 mm, 3313 0.089 mm, 2113 0.089 mm, 2116 0.114 mm, 7628 0.190 mm. The same style can be supplied at several resin contents, which moves thickness by ±15% or more; the thickness guide lists the ranges.
Assumptions: the layer count is even and built by foil construction (outer dielectrics are prepreg, inner dielectrics alternate core and prepreg). Prepreg is counted at nominal thickness; in a real press cycle prepreg resin fills etched copper on adjacent layers, so pressed thickness is usually lower. Outer-layer plating, solder mask and surface finish are not included and typically add about 0.05–0.10 mm. Aspect ratio uses finished hole size; drilled size is larger by the plating allowance, which makes the true drilled aspect ratio slightly lower.
Warnings: aspect ratio above 10:1 is flagged yellow and above 12:1 red, both with "confirm with fabricator"; plating capability varies by partner and process. A total thickness above 3.0 mm triggers a note to consider T-glass or low-CTE construction for plated through-hole reliability, following the rule in our T-glass guide.
This is a planning estimate. The released stackup comes from the fabricator's own pressed-thickness calculation.
Request a stackup review
A stackup review returns the fabricator's pressed-thickness calculation, impedance per layer and named CCL and glass constructions, usually within five business days.