Standard PCB Thickness: Sizes, Charts, and FR4 Specifications

The de facto standard finished PCB thickness is 1.57 mm (0.062 in, rounded). Many metric ordering systems list 1.60 mm instead. The value descends from historic 1/16 in stock, but it is a default rather than a universal requirement.

Common PCB Thicknesses in Millimeters and Inches

The inch column uses 25.4 mm per inch. Exact 1/16 in stock is 0.0625 in, or 1.5875 mm. The 1.57 mm nominal converts to 0.0618 in before rounding.

How to Select PCB Thickness

These values are industry-typical nominal choices, not guaranteed OurPCB capabilities. Confirm material, layer count, copper, finished thickness, and tolerance when requesting a quotation.

What Does Finished PCB Thickness Include?

Finished thickness is an overall stackup result. IPC-2222A says the calculation includes pressed dielectrics, base laminate, copper foils, and plating. Its reference tolerance levels use laminate-to-laminate measurement. Finishes or coatings need separate consideration when they are part of the measurement.

Put the nominal value, tolerance, and measurement basis on the fabrication drawing. Do not substitute a core or prepreg thickness for the required finished board thickness.

What Factors Influence PCB Thickness?

Overall thickness comes from the complete stackup. Select it after checking the material system, layer count, copper, dielectric spacing, and mechanical interfaces. A single layer count does not imply one fixed finished thickness.

Material system

The selected laminate system determines which cores and prepregs are available. Review the electrical, thermal, and mechanical requirements before choosing from the available PCB materials. The fabricator then resolves those materials into a manufacturable stackup.

Copper thickness

Copper thickness is not the same as finished board thickness. Copper weight is commonly specified in ounces per square foot. One ounce corresponds to about 35 µm, while two ounces corresponds to about 70 µm.

Copper and trace geometry govern current-carrying design. Do not treat a thicker finished board as a substitute for the required copper specification.

Core, prepreg, and dielectric spacing

Cores and prepregs form the insulating spacing between conductive layers. For a multilayer build, the pressed dielectric thicknesses, copper, and their accumulated tolerances contribute to the finished result. Use the fabricator's pressed stackup values, not an assumed unpressed prepreg thickness.

Layer count

Layer count constrains achievable thickness, but it does not determine one standard value. Current fabrication catalogs show that both two-layer and four-layer FR-4 boards can be offered at several finished thicknesses.

As layers are added, the fabricator must fit more copper and dielectric separations inside the target. Request a stackup review before fixing a thin multilayer thickness.

PCB Thickness Tolerance

Finished PCB thickness tolerance is normally specified as a percentage. For boards at least 1.0 mm thick, ±10% is an industry-typical commercial starting point, not a universal guarantee. At that tolerance, a 1.60 mm board can measure from 1.44 mm to 1.76 mm.

Thin boards, card edges, and other mechanical interfaces can use different limits. State the required percentage or interface-specific band on the drawing, then obtain fabricator agreement.

Environmental requirements

Choose material and thickness from the product's documented environmental and mechanical requirements. Thickness alone does not establish thermal, humidity, vibration, or reliability performance.

Why is PCB Thickness Important in Design?

Finished thickness affects mechanical fit and the stackups available to the designer. It can also limit connector compatibility and dielectric spacing. It does not, by itself, set current capacity, thermal performance, or controlled impedance.

Electrical Performance

Overall thickness affects the space available for dielectric layers, but impedance depends on the approved stackup. Review dielectric spacing, copper, trace geometry, and reference planes together. See the controlled impedance PCB guide for that workflow.

For current capacity, specify copper thickness and conductor geometry. Finished board thickness is a separate mechanical and stackup requirement.

How Does the Thickness of PCBs Affect Manufacturing?

Finished thickness is one input to fabrication planning, but it does not by itself determine process difficulty or cost. The fabricator evaluates the complete stackup, materials, copper requirements, hole sizes, tolerances, and order details.

Drilling Equipment Limitations

IPC-2222A section 9.2.2.1 identifies two separate effects: a higher hole aspect ratio makes hole plating more difficult, while increased board thickness independently increases drill bit wander risk. Confirm the permitted aspect ratio and drilling limits with the fabricator.

How to Choose the Right PCB Thickness

Start with every fixed interface, then work inward. Check connector drawings, the enclosure, mounting hardware, and height limits. Next confirm layer count, material, copper, dielectric spacing, and impedance needs with the fabricator. Finally, state the nominal finished thickness and tolerance on the drawing.

Weight Considerations

Use the product's mass budget rather than a generic thickness rule. Board area, material, copper, and attached hardware all contribute to assembly mass.

Assembly Components Requirements

Connector, card-edge, and mounting drawings can impose a specific board thickness and tolerance. Use those interface requirements before choosing a general nominal value.

Specific Application Needs

There is no single thickness for every application. Select the thinnest approved stackup that still meets the electrical, mechanical, assembly, and fabrication requirements.

Electrical Requirements

Use the fabricator-approved dielectric stackup for impedance. Use copper thickness and trace geometry for current. Neither requirement is defined by the finished board thickness alone.

Physical Space Constraints

Check the full thickness tolerance band against the enclosure, slots, guides, and mating hardware. A nominal value can fit while its allowed upper limit does not.

Using a Trace Width Calculator

A trace-width calculation uses current, copper thickness, and allowable temperature rise. Finished PCB thickness is not the copper-thickness input. Keep both values as separate fabrication requirements.

How Does PCB Thickness Impact Cost?

Finished thickness alone does not determine price. Material system, stackup, copper requirements, hole aspect ratios, tolerances, order quantity, and other fabrication details can affect a quotation. Treat temperature exposure as a separate material requirement and review the high-temperature PCB guide when it applies.

When Should Custom PCB Thickness Be Considered?

Use a custom finished thickness when a connector, enclosure, approved impedance stackup, or mechanical analysis requires it. Obtain fabricator agreement before releasing the board data.

Key Considerations for Custom-Thickness PCBs

• Nominal finished thickness and percentage tolerance
• Measurement basis, including any coating or finish requirement
• Material system, layer count, and copper for every layer
• Approved core, prepreg, and controlled-impedance stackup
• Connector, card-edge, enclosure, and mounting constraints

How Are Custom-Thickness PCBs Manufactured?

The fabricator selects cores and prepregs, predicts pressed dielectric thickness, and accounts for copper and plating. The proposed stackup should show how those elements meet the nominal finished thickness and tolerance. Approve that stackup before fabrication.

PCB Thickness FAQs

These answers separate finished thickness from the electrical properties that are often confused with it.

Is 1.6 mm the same as 0.062 in?

Not exactly. A 1.60 mm nominal converts to 0.0630 in. A 1.57 mm nominal converts to 0.0618 in and is commonly rounded to 0.062 in. Exact 1/16 in stock is 0.0625 in, or 1.5875 mm.

Does a thicker PCB carry more current?

Not by itself. Current-carrying design depends on copper thickness, conductor geometry, temperature rise, and the surrounding stackup. Specify copper weight separately from finished board thickness.

Can a four-layer PCB be 1.6 mm thick?

Yes, 1.6 mm four-layer builds are offered commercially. The same layer count can also use other finished thicknesses. The fabricator must confirm the exact core, prepreg, copper, and dielectric construction.