Standard PCB thickness
PCB thickness is the overall thickness of a finished printed circuit board. The standard is 1.6 mm (about 0.062 inch), but boards from around 0.4 mm to 3.2 mm and more are common. Thickness is set by the stack-up of cores, prepreg and copper, and affects stiffness, connectors, impedance and cost.
PCB thickness explained
The finished thickness of a PCB is the sum of its layers: the laminate cores, the prepreg between them, the copper foil and plating, and the solder mask and surface finish on the outside. For a multilayer PCB the combination is defined in the stack-up.
The 1.6 mm standard has historical roots. Early boards were built on laminate sheets about 1/16 inch thick, a size already used for other materials, and edge connectors, card guides and board-to-board hardware were designed around it. The value stuck, and today materials, tooling and processes are optimised for 1.6 mm boards. As a result it is usually the easiest and most economical thickness to build.
Other thicknesses are common. Thin boards around 0.8 mm or 1.0 mm save space and weight in compact devices. Thick boards of 2.0 mm, 2.4 mm or 3.2 mm give extra stiffness for large or heavy assemblies, backplanes and boards with press-fit connectors, and leave room for high layer counts.
Thickness must be specified with a tolerance, and the measurement method should be stated. A board can be measured over the outer copper and plating, over the solder mask, or as laminate only. These can differ by a noticeable amount, so the drawing should say which applies. Tolerances of around ±10% are common for standard boards; tighter tolerances may be possible but should be agreed with the manufacturer.
Thickness also sets the aspect ratio of plated holes — board thickness divided by drill diameter — which limits how small through-holes can be.
When PCB thickness matters
Thickness matters wherever the board meets something mechanical. Card-edge connectors and card guides need the correct thickness to fit and make reliable contact. Enclosures, mounting hardware and press-fit pins also assume a specific value.
It affects electrical design. In controlled impedance designs, the dielectric thickness between a trace and its reference plane sets the impedance, so the overall thickness and the stack-up have to be decided together.
It affects reliability and assembly. Thin boards can warp during reflow or flex too much in use; thick boards with small vias have high aspect ratios that are harder to plate. Large panels of thin boards may need extra support during assembly. For flex PCBs and boards with stiffeners, thickness is specified per area rather than as a single value.
Common PCB thicknesses compared
Always state the tolerance and whether thickness is measured over copper and plating, over solder mask or as laminate only. Thinner boards save space and weight but flex more; thicker boards are stiffer but raise the aspect ratio of small plated holes. When in doubt, start from 1.6 mm and change it only for a clear reason.
PCB thickness in your quote request
In your quote request, state the finished board thickness, the tolerance and how it is measured — over plating, over solder mask or laminate only. If an edge connector, enclosure or press-fit part depends on the thickness, say so. For multilayer and impedance-controlled boards, include the stack-up or your impedance targets so the manufacturer can propose a build that meets both. Our free DFM check flags plated holes whose aspect ratio may be difficult at the chosen thickness.
Need boards built? Upload your Gerber files for a free quote and DFM check from the right manufacturer in our network.
PCB manufacturing →FAQ about PCB thickness
What is the standard PCB thickness?
The standard PCB thickness is 1.6 mm, or about 0.062 inch. It is the default in most design tools and the value manufacturers are best set up for, so it is usually the most economical choice. Other common finished thicknesses include 0.8 mm, 1.0 mm, 1.2 mm, 2.0 mm and 2.4 mm, chosen for space, weight, stiffness or connector requirements.
Why are PCBs 1.6 mm thick?
PCBs are commonly 1.6 mm thick because early boards were made from laminate sheets about 1/16 inch thick, and connectors, card guides and other hardware were designed around that size. The industry standardised on it, so materials, tooling and processes are optimised for 1.6 mm. Electrically there is nothing special about it; it is a mechanical and historical standard.
How thick is a 4-layer PCB?
A 4-layer PCB is most often built to the standard 1.6 mm finished thickness, using a central core with prepreg and copper foil on each side. It can also be built thinner or thicker, for example 0.8 mm, 1.0 mm or 2.0 mm, by changing the core and prepreg thicknesses. The layer count does not fix the thickness; the stack-up does.
Related terms
- Stack-up
A PCB stack-up is the cross-sectional arrangement of copper layers, cores and prepreg that make up a multilayer board. It defines the layer order, dielectric thicknesses, copper weights and material properties. The stack-up is critical for controlled impedance, signal integrity, EMC performance and manufacturability, and it should be agreed with the manufacturer before layout is finalised.
- Multilayer PCB
A multilayer PCB is a printed circuit board with three or more copper layers, separated by insulating dielectric and laminated together under heat and pressure. Inner layers carry signals or form solid power and ground planes, and plated vias connect the layers. Most multilayer boards use an even number of layers, such as four, six or eight.
- FR-4
FR-4 is a flame-retardant laminate made of woven fibreglass cloth bonded with epoxy resin. It is the default base material for most rigid PCBs because it balances mechanical strength, electrical insulation, thermal performance and cost. Variants exist for high-Tg, halogen-free and high-speed applications, and the grade is chosen to suit the assembly process and operating conditions.
- Copper weight
Copper weight is the thickness of copper foil on each PCB layer, specified in µm or ounces per square foot. Common weights are 18 µm (0.5 oz), 35 µm (1 oz), and 70 µm (2 oz). Heavier copper carries more current and dissipates more heat but limits minimum trace width.
- Impedance control
Impedance control is the practice of specifying and manufacturing PCB traces so their characteristic impedance meets a precise target — typically 50 Ω single-ended or 100 Ω differential. Required for high-speed digital, RF, and signal integrity-critical designs, it depends on trace width, dielectric thickness, copper weight, and material properties.
- Rigid PCB
A rigid PCB is a printed circuit board built on a solid, inflexible substrate, most often glass-reinforced epoxy laminate such as FR-4. It holds its shape in service and supports components mechanically. Rigid boards are the most common type of PCB and range from simple single-sided boards to complex multilayer designs.