1.6mm PCB: Why It Became the Industry Standard & Complete Design Guide

If you’ve ever ordered a PCB prototype or looked at manufacturer specifications, you’ve probably noticed that 1.6mm PCB thickness appears as the default option everywhere. This isn’t a coincidence. The 1.6mm PCB has earned its place as the global industry standard through decades of optimization, and understanding why can help you make better design decisions.

In this guide, I’ll explain exactly how 1.6mm became the dominant thickness, when you should use it, when you shouldn’t, and provide complete stackup configurations for multilayer designs. Whether you’re designing your first board or your hundredth, this information will save you time and help you avoid costly mistakes.

What is a 1.6mm PCB?

A 1.6mm PCB refers to a printed circuit board with a total finished thickness of 1.6 millimeters (approximately 0.063 inches or 63 mils). This measurement includes all layers of the board: the FR-4 substrate, copper layers, prepreg materials, solder mask, and surface finish.

The 1.6mm thickness represents what most manufacturers consider their “standard” offering. When you submit a design without specifying thickness, your fabricator will almost certainly default to 1.6mm. This standardization means faster production times, lower costs, and predictable results.

How 1.6mm Became the Global PCB Standard

The dominance of 1.6mm PCB thickness didn’t happen by accident. It traces back to the early days of printed circuit board manufacturing, and understanding this history helps explain why it remains the standard today.

The Origin Story: From Imperial to Metric

During the vacuum tube era, when the PCB industry was just beginning, manufacturers needed a thickness that could provide adequate mechanical support for heavy components while remaining practical to produce. The material of choice was phenolic laminate, and the standard production thickness was 1/16 inch.

When the electronics industry transitioned to metric measurements, 1/16 inch converted to approximately 1.5875mm. Different regions rounded this differently: some use 1.57mm, others 1.58mm, and most simply round to 1.6mm. This is why you’ll occasionally see specifications listing 1.57mm as the “standard” thickness. They’re all referring to the same original imperial dimension.

Why the Industry Standardized on This Thickness

Several factors cemented 1.6mm as the default choice.

Connector Compatibility: Board-to-board connectors, edge connectors, and card slots were designed around the 1/16 inch specification. PCIe slots, ISA connectors, and countless other interface standards assume this thickness. Deviating from 1.6mm means risking compatibility issues with standard connectors.

Manufacturing Economics: Fabricators optimized their processes, equipment, and material inventories around 1.6mm boards. Lamination presses, drilling machines, and handling equipment all work most efficiently with this thickness. Non-standard thicknesses require process adjustments that increase cost and lead time.

Mechanical Balance: The 1.6mm thickness provides an optimal balance between rigidity and weight. Boards are stiff enough to support through-hole components and withstand handling during assembly, yet thin enough to fit in most enclosures without excessive material cost.

IPC Standardization: Industry standards like IPC-2221 specify 1.6mm as the baseline thickness for general-purpose PCBs, giving engineers and manufacturers a common reference point.

Key Benefits of 1.6mm PCB Thickness

Before choosing a PCB thickness, you need to understand what 1.6mm boards do well. Here’s why the standard thickness works for the majority of applications.

Mechanical Strength and Durability

A 1.6mm PCB provides excellent rigidity for boards up to approximately 200mm x 200mm without requiring additional stiffeners. The board can support heavy components like large transformers, heat sinks, and through-hole connectors without flexing during assembly or operation.

Thermal Performance

Thicker boards generally dissipate heat more effectively than thinner alternatives. The additional FR-4 material acts as a thermal mass, helping to spread and absorb heat from power components. For designs with moderate power dissipation, 1.6mm provides adequate thermal management without requiring special materials.

Signal Integrity for High-Speed Design

The 1.6mm thickness accommodates proper impedance-controlled stackups. With adequate dielectric spacing between signal and reference planes, you can achieve controlled impedance traces (typically 50Ω single-ended or 100Ω differential) using practical trace widths. Thinner boards compress these spacings, making impedance control more difficult with standard PCB manufacturing tolerances.

Cost Effectiveness

Because 1.6mm is the industry standard, it’s also the most economical choice for most projects.

1.6mm PCB Stackup Configurations

One advantage of 1.6mm thickness is its versatility across different layer counts. Here are standard stackup configurations you can use directly in your designs.

2-Layer 1.6mm PCB Stackup

The simplest configuration, ideal for low-complexity designs with modest routing density.

This stackup works well for simple power supplies, LED drivers, and basic control circuits where signal integrity isn’t critical.

4-Layer 1.6mm PCB Stackup

The workhorse configuration for most embedded systems and moderate-complexity designs.

With dedicated ground and power planes, this stackup provides good EMI performance and supports impedance-controlled routing on the outer layers.

6-Layer 1.6mm PCB Stackup

For high-speed digital designs, mixed-signal circuits, or dense routing requirements.

This configuration places signal layers adjacent to reference planes, providing excellent EMI shielding and stable impedance control. The thicker prepreg in the middle reduces crosstalk between internal signal layers.

8-Layer 1.6mm PCB Stackup

For complex designs requiring maximum routing density within standard thickness.

Note that 8-layer boards in 1.6mm thickness require thin cores and prepregs. This makes impedance control more challenging and may require closer coordination with your fabricator.

Read more Different PCB Thickness:

0.1mm PCB: The Complete Guide to Ultra-Thin Circuit Boards

0.2mm PCB: Complete Guide to Thin Circuit Board Design & Manufacturing

0.4mm PCB: The Starting Point for Multilayer Circuit Board Design

0.6mm PCB: The First Thickness Supporting All Surface Finishes

0.8mm PCB: Complete Guide to Half-Thickness Board Design & Applications

1.2mm PCB Thickness Guide: Perfect Balance Between Flexibility & Durability

1.5mm PCB: The Often Overlooked Standard Thickness Explained

1.6mm PCB: Why It Became the Industry Standard & Complete Design Guide

1.8mm PCB: The Non-Standard Thickness for Multilayer Board Design

2.0mm PCB: The Heavy-Duty Thickness for Industrial & High-Power Applications

2.4mm PCB: The Ultimate Thick Board Guide for High-Power & Extreme Applications

2.8mm PCB Thickness: When Standard Options Don’t Fit Your Design

3.0mm PCB: Complete Guide for Heavy-Duty Boards Without the 3.2mm Overkill

4.2mm PCB: Custom Backplane Thickness for When 4.0mm Falls Short

4.8mm PCB: Heavy-Duty Backplane Thickness When You Need Nearly 5.0mm Performance

5.6mm PCB: The Ultra-Thick Sweet Spot Between 5.0mm and 6.0mm Backplanes

Best Applications for 1.6mm PCB

The 1.6mm thickness excels in a wide range of applications. Here’s where it makes the most sense.

Industrial Control Systems

Industrial environments demand reliability. The 1.6mm thickness provides mechanical robustness to withstand vibration, temperature cycling, and rough handling during installation and maintenance. PLCs, motor controllers, and instrumentation systems commonly use 1.6mm boards.

Computer Motherboards and Expansion Cards

PC motherboards, graphics cards, and expansion cards rely on 1.6mm thickness for edge connector compatibility. PCIe, DIMM, and other standard slots expect this thickness for proper contact alignment and retention.

General Consumer Electronics

Television controllers, home appliances, audio equipment, and similar products benefit from the cost-effectiveness and availability of 1.6mm PCBs. The thickness provides adequate performance without premium pricing.

Automotive Electronics

While some automotive applications use thicker boards for extreme durability, many ECUs, body controllers, and infotainment systems use 1.6mm boards with appropriate material grades (high-Tg FR-4 or similar).

Power Electronics

Moderate-power supplies, battery management systems, and LED drivers often use 1.6mm boards. The thickness supports adequate copper weight for current-carrying traces while providing mechanical support for transformers and heat sinks.

When NOT to Use 1.6mm PCB

While 1.6mm works for most applications, some designs benefit from different thicknesses.

Compact Mobile Devices

Smartphones, tablets, and wearables need every fraction of a millimeter. These devices typically use 0.8mm to 1.0mm boards to minimize overall product thickness.

Ultra-Thin Form Factors

Credit card-sized devices, smart cards, and similar applications may require boards as thin as 0.4mm to 0.6mm.

High-Power Industrial Equipment

Heavy industrial equipment with large transformers, high-current busbars, or extreme vibration may benefit from 2.0mm to 2.4mm boards for additional strength.

Specific Connector Requirements

Some specialized connectors require non-standard thicknesses. Always verify connector specifications before finalizing board thickness.

1.6mm PCB vs Other Thicknesses: Detailed Comparison

Here’s how 1.6mm compares to other common thickness options across multiple parameters.

Manufacturing Considerations for 1.6mm PCB

Understanding manufacturing aspects helps you design boards that fabricators can build reliably.

Drilling Aspect Ratios

The aspect ratio (board thickness ÷ hole diameter) affects plating quality in through-holes.

For 1.6mm boards, keep minimum hole diameters at 0.25mm or larger for standard fabrication. Smaller holes may require advanced processes.

Warpage Prevention

Even at 1.6mm, boards can warp if copper distribution is uneven. Follow these guidelines to minimize warpage.

Maintain symmetric copper distribution between top and bottom layers. Keep inner layer copper percentages within 20% of each other between opposing layers. Use adequate ground fill on signal layers. Avoid concentrating heavy copper pours on one side of the board.

Surface Finish Selection

All standard surface finishes work well with 1.6mm boards.

Design Tips for 1.6mm PCB Projects

After working with countless 1.6mm board designs, here are practical tips that will save you trouble.

Tip 1: Verify Connector Specifications Early Before finalizing your stackup, check all connector datasheets for PCB thickness requirements. Some connectors specify exact thickness ranges that may not align with your initial assumptions.

Tip 2: Communicate Stackup Requirements Clearly Don’t assume your fabricator will use the stackup you want. Specify layer count, thickness, and impedance requirements explicitly in your fabrication notes. Request stackup confirmation before production.

Tip 3: Consider Panelization Effects Large panels with multiple boards can exhibit more warpage than single boards. If you’re panelizing, discuss panel size with your fabricator and consider adding tooling holes for better support during processing.

Tip 4: Account for Thickness Tolerance in Enclosure Design With ±10% tolerance, a 1.6mm board could be anywhere from 1.44mm to 1.76mm. Design enclosure slots and mounting features to accommodate this range.

Tip 5: Use Standard Prepreg and Core Combinations Exotic stackups require special material orders. Stick to standard prepreg types (1080, 2116, 7628) and common core thicknesses for fastest delivery and lowest cost.

Useful Resources for 1.6mm PCB Design

These tools and references will help you work with 1.6mm PCB designs effectively.

Impedance Calculators

Saturn PCB Design Toolkit: Free Windows application with trace impedance, via current, and thermal calculations. Download from saturnpcb.com.

JLCPCB Impedance Calculator: Online tool specifically calibrated for JLCPCB’s stackups and materials. Access at jlcpcb.com/impedance-calculator.

Stackup References

PCBWay Standard Stackups: Comprehensive library of pre-defined stackups for various layer counts and thicknesses. Available at pcbway.com/multi-layer-laminated-structure.html.

Industry Standards

IPC-2221: Generic Standard on Printed Board Design. Defines baseline requirements including the 1.6mm standard thickness.

IPC-4101: Specification for Base Materials for Rigid and Multilayer Printed Boards. Details FR-4 material properties.

Material Databases

Isola Laminate Selector: Compare properties of different laminate materials at isola-group.com.

Rogers Corporation Design Tools: High-frequency material data and calculators at rogerscorp.com.

Frequently Asked Questions

Why is 1.6mm considered the standard PCB thickness?

The 1.6mm standard originated from the imperial measurement of 1/16 inch (approximately 0.0625 inches or 63 mils), which was the production thickness of early phenolic laminates. As PCB technology evolved, connectors and manufacturing processes were optimized around this dimension. Industry standards like IPC-2221 formalized 1.6mm as the baseline, and the economics of standardization have kept it dominant ever since.

Can I fit 6 or 8 layers in a 1.6mm PCB?

Yes, 6-layer and 8-layer designs are entirely practical in 1.6mm thickness. Six-layer boards are common and straightforward with standard materials. Eight-layer boards require thinner cores and prepregs, which makes impedance control more sensitive to manufacturing tolerances. Work closely with your fabricator to verify their standard 8-layer 1.6mm stackup meets your requirements.

What’s the difference between 1.6mm, 1.57mm, and 62 mil PCB specifications?

These all refer to the same original dimension. The imperial measurement of 1/16 inch equals 1.5875mm, which different sources round to 1.57mm, 1.58mm, or 1.6mm depending on regional convention. North American sources often cite 0.062″ (62 mils), European sources commonly use 1.5mm or 1.6mm, and Asian manufacturers typically specify 1.6mm. For practical purposes, they’re interchangeable.

Is 1.6mm PCB suitable for high-frequency RF designs?

For moderate RF frequencies (up to several GHz), standard 1.6mm FR-4 boards work adequately. The thickness allows proper spacing for impedance control. However, for demanding RF applications above 3-5 GHz, you may need specialized materials (Rogers, Taconic, etc.) regardless of thickness. The limiting factor becomes material properties rather than board thickness.

How does 1.6mm PCB thickness affect assembly?

Standard SMT assembly processes are optimized for 1.6mm boards. Pick-and-place machines, reflow ovens, and wave soldering equipment handle this thickness without adjustment. Thinner boards (0.8mm or less) may require carrier fixtures to prevent warping during reflow. Thicker boards may need modified thermal profiles. Sticking with 1.6mm simplifies assembly and reduces risk.

Conclusion

The 1.6mm PCB has earned its position as the industry standard through decades of proven performance. Its balance of mechanical strength, thermal capacity, manufacturing economics, and design flexibility makes it the right choice for the majority of electronic products.

When designing your next board, start with 1.6mm as your default assumption. Only deviate from this standard when your specific requirements genuinely demand a different thickness. By working within established norms, you’ll benefit from faster fabrication, lower costs, and more predictable results.

Understanding why 1.6mm became standard helps you make informed decisions about when to use it and when alternatives make more sense. The stackup configurations and design guidelines in this article give you practical starting points for your own projects, whether you’re building a simple 2-layer prototype or a complex 8-layer production board.