In PCB design and selection, 1.6mm is a number you simply cannot get around. More than 70% of circuit boards use this thickness. Yet the figure did not come from any theoretical formula — it is the "performance–cost–process" equilibrium point forged by decades of high-volume manufacturing practice in the electronics industry.
The Historical Origin of 1.6mm
In the early days of the PCB industry, substrates were mostly phenolic resin paper-based laminates (bakelite boards), and the most reliably available nominal thickness on the market at the time was 1/16 inch. FR-4 later became the mainstream substrate, but by then the conveyor rails of automated production lines, the board-edge connector slots, wave soldering fixtures, and even component lead lengths had all matured into a complete industrial ecosystem built around 1.6mm. The specification has carried forward ever since and is now the industry's default "reference thickness."
The Structural Advantages of 1.6mm
From a mechanical standpoint, a board's bending stiffness scales with the cube of its thickness. 1.6mm strikes the optimal balance among rigidity, manufacturing maturity, cost, and connector compatibility. Standard PCIe slots and virtually all card-edge connectors are designed around 1.6mm — choosing 1.6mm means you don't have to source custom connectors just to accommodate your board thickness.
The Limitations of 1.6mm
But 1.6mm is not a universal answer. A 1.6mm board won't fit inside a smart wristband's housing, while an 0.8mm thin board in industrial control equipment can crack from insufficient mechanical strength. Board thickness is not something you design — it is the optimal solution forced out by the combined pressures of structure, electrical performance, and manufacturing process. Consumer electronics chase thinness and lightness, while server backplanes may need twenty-plus layers of high-density routing — clinging to a single board thickness can no longer meet today's design demands.
The Industry-Standard Thickness Matrix
The industry's common thickness range today spans 0.2mm to 3.2mm. Frequently used specifications include: 0.4mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.6mm, 2.0mm, and 2.4mm. These values were not divided up arbitrarily; each is an equilibrium point formed through long-term practice.
For most devices without special requirements, 1.6mm is a reliable starting point — it delivers good rigidity without adding unnecessary cost. But if your product has specific structural constraints or electrical requirements, you'll need to find a better match within the standard matrix.
Home > 
