PCB Layer Stackup Planner (2/4/6/8-Layer)
Plan a PCB layer stack with copper weights, dielectric heights, FR4 Dk values, and finished thickness — 2 to 8 layers.
- Copper layers
- 4
- Total thickness
- 1.600 mm
- Dielectric material
- FR4
- FR4 Dk (εr)
- 4.3
FR4 dielectric constant (εr): ~4.3 at 1 GHz (industry-standard nominal). Actual values range 4.0–4.7 depending on resin content and frequency. Rogers substrates (RO4350B, RO4003C) run 3.55–3.66 for lower loss and tighter impedance control.
Standard PCB thickness: 1.6 mm (0.063") is the default for most 2 and 4-layer boards. Copper weight is quoted in oz/ft² — 1 oz = 0.035 mm (35 µm) thick. Signal integrity increasingly depends on stackup consistency; specify plate-to-plate spacing to the fab, not just total thickness.
How to choose 2 vs 4 vs 6 layers
2-layer: hobby, breakout, low-speed. 4-layer: most production boards — signal/GND/PWR/signal gives you a ground reference under every signal. 6-layer: mixed-signal, controlled impedance, EMC-sensitive. 8-layer+: BGA-heavy, high-speed (DDR, PCIe), power-heavy with multiple rails needing dedicated planes.
Symmetric stackups avoid warping
PCBs warp during reflow if the stackup isn't symmetric about the middle. Copper distribution, dielectric heights, and core/prepreg placement should all mirror the centreline. The 4/6/8-layer presets here are symmetric by construction.
Match stackup to fab capabilities
Different fab houses have different standard offerings. JLCPCB's standard 4-layer has 0.2 mm prepreg + 1.06 mm core. PCBWay is similar. Always download your fab's stackup PDF before running impedance calculations — the exact dielectric heights determine the trace geometry you need.
Frequently asked
- What is FR4 dielectric constant?
- Nominally 4.3 at 1 GHz. Actual varies 4.0–4.7 depending on glass/resin ratio and frequency. Most impedance calculators use 4.3 as a starting point; verify with your fab's datasheet for critical designs.
- How thick is a standard PCB?
- 1.6 mm (0.063") is the default for most 2 and 4-layer boards. Common alternatives: 0.8 mm (thin), 1.0 mm, 2.0 mm, 2.4 mm (thicker for through-hole/mechanical strength).
- How to pick copper weight?
- 1 oz (35 µm) is the standard default. Use 2 oz for high-current traces (>3 A sustained) or motor drives. Use ½ oz for fine-pitch fanout. Heavier copper limits trace-space minima.
- Do I need a stackup drawing for the fab?
- For impedance-controlled designs, yes — send the fab the exact stackup and require impedance verification. For simple 2-layer digital boards the standard defaults are fine.
Decided on the layer count? PCBEditor asks for it before laying out the board, and puts power and ground on the planes you choose.
Design a board with this stackup →Related free tools
- Microstrip Impedance Calculator (IPC-2141)Characteristic impedance for a trace on an outer layer above a ground plane, per IPC-2141.
- PCB Trace Width Calculator (IPC-2221)Minimum copper trace width for a given current + temperature rise, per IPC-2221. Supports internal and external layers, 0.5–3 oz copper.
- Via Current Capacity Calculator (IPC-2152)Max current for a plated-through-hole via, by barrel diameter, plating thickness, and allowed temperature rise.