What is .PcbDoc? Altium Designer PCB Format Explained

After years of designing PCBs professionally, I’ve worked with just about every file format the industry has to offer. But when clients or colleagues ask me to recommend a PCB design platform, Altium Designer consistently comes up—and with it, the .PcbDoc file format. If you’ve ever received design files from another engineer, collaborated on a project, or tried to convert between different EDA tools, understanding .PcbDoc is essential knowledge.

This comprehensive guide covers everything you need to know about .PcbDoc files: what they contain, how they work, how to open and convert them, and why they’ve become the professional standard for serious PCB design work.

Understanding the .PcbDoc File Format

The .PcbDoc extension identifies a PCB Document file native to Altium Designer, the professional-grade electronic design automation (EDA) software developed by Altium Limited. This file format serves as the primary container for printed circuit board layout data within the Altium Designer environment.

Unlike manufacturing output formats such as Gerber files that only contain layer images, a .PcbDoc file stores the complete, editable PCB design including all the intelligence that makes modification and analysis possible. Think of Gerber files as photographs of your design—they show what it looks like but you can’t change them. A .PcbDoc file is the actual design itself, with every object, connection, and constraint preserved and editable.

The format has evolved continuously since Altium Designer 6.0 launched in 2005, building on the legacy of Protel software that dominated PCB design in the 1990s and early 2000s. Today’s .PcbDoc files support advanced features that weren’t conceivable two decades ago: embedded 3D component models, rigid-flex definitions, advanced design rules, and direct integration with cloud collaboration platforms.

What Data Does a .PcbDoc File Contain?

A .PcbDoc file stores comprehensive PCB design information organized into logical sections:

The format uses a proprietary binary structure, though Altium Designer can also save files in ASCII format for improved compatibility with third-party import tools. The binary format offers faster load times and smaller file sizes, while ASCII format provides better interoperability when sharing designs with users of other EDA platforms.

.PcbDoc vs .PCB: Understanding the Difference

Engineers transitioning from legacy systems often confuse .PcbDoc with the older .PCB format. While both contain PCB design data, they represent different eras of the same software lineage.

When Altium Designer opens a legacy .PCB file, the Import Wizard automatically handles conversion to the modern .PcbDoc format. However, this conversion may lose some legacy features while gaining access to all modern capabilities. For archival purposes, keeping both the original .PCB and converted .PcbDoc is wise practice.

Inside the .PcbDoc File Structure

Understanding the internal organization of .PcbDoc files helps when troubleshooting issues or working with conversion tools. The file uses a compound document format similar to Microsoft’s OLE structure, containing multiple embedded streams of data.

Binary vs ASCII .PcbDoc Formats

Altium Designer supports saving .PcbDoc files in two internal formats:

Binary Format (Default) The standard binary format packages all design data into a compact, efficient structure optimized for Altium Designer’s internal operations. Binary files load faster and consume less disk space but require Altium software to interpret.

ASCII Format The ASCII version saves the same data in a text-based format that other tools can parse. While larger in file size, ASCII .PcbDoc files enable:

• Import into KiCad, EasyEDA Pro, and other EDA tools
• Version control systems to show meaningful diffs
• Third-party converter scripts to process the data
• Manual inspection and repair of corrupted files

To save as ASCII in Altium Designer, use File > Save Copy As and select “PCB ASCII File (*.PcbDoc)” from the format dropdown. This creates a duplicate file while preserving your original binary version.

Key Internal Components

A .PcbDoc file contains several major data sections:

How to Open .PcbDoc Files

Opening .PcbDoc files requires appropriate software, though options exist beyond the official Altium Designer application.

Primary Software Options

Opening .PcbDoc in Altium Designer

For users with Altium Designer access, opening .PcbDoc files is straightforward:

1. Launch Altium Designer
2. Select File > Open from the main menu
3. Navigate to the .PcbDoc file location
4. Select the file and click Open

The PCB Editor workspace activates automatically, displaying your design with full editing capabilities. If the file belongs to a project, Altium prompts you to open the associated .PrjPcb project file for complete design context.

Using the Free Altium 365 Viewer

For viewing without editing, Altium provides a free browser-based solution at altium.com/viewer. This tool supports:

• Direct upload of .PcbDoc and .SchDoc files
• Interactive 2D layer viewing
• Full 3D board visualization
• BOM extraction and review
• Design sharing via temporary links

The viewer accepts files up to certain size limits and doesn’t require account creation for basic viewing, making it ideal for quick reviews or sharing designs with clients who don’t have Altium installed.

Opening .PcbDoc in KiCad

Since KiCad 7, the open-source EDA tool has supported direct import of Altium .PcbDoc files. The process works as follows:

1. Launch KiCad and create a new project
2. Open the PCB Editor (Pcbnew)
3. Select File > Import Non-KiCad Board File
4. Choose Altium Designer PCB as the file type
5. Navigate to and select your .PcbDoc file
6. Complete the layer mapping dialog

KiCad preserves most design elements during conversion, though complex features like embedded 3D models may require manual adjustment. For best results, use KiCad 9 or later, which includes significant improvements to Altium import fidelity.

Converting .PcbDoc Files to Other Formats

Converting .PcbDoc files enables collaboration with engineers using different tools and prepares designs for manufacturing.

.PcbDoc to Gerber Conversion

For PCB fabrication, manufacturers need Gerber files—the universal manufacturing format. In Altium Designer:

1. Open your .PcbDoc file
2. Navigate to File > Fabrication Outputs > Gerber Files
3. Configure layer selection and format options
4. Click OK to generate the files
5. Repeat for NC Drill Files under the same menu

A complete manufacturing package includes:

.PcbDoc to ODB++ Conversion

The ODB++ format bundles all manufacturing data into a single intelligent package. In Altium Designer:

1. Open your .PcbDoc file
2. Select File > Fabrication Outputs > ODB++
3. Configure layer and option settings
4. Choose output directory
5. Click OK to generate

ODB++ advantages over Gerber include embedded net information, component data, and stackup definitions—reducing the chance of manufacturing errors from misinterpreted files.

.PcbDoc to KiCad Conversion

Beyond direct import, dedicated converters exist for Altium-to-KiCad conversion:

altium2kicad (Open Source) A Perl-based converter available at github.com/thesourcerer8/altium2kicad that processes .PcbDoc files (must be saved in ASCII format) and outputs KiCad-compatible files.

Futureware Online Converter A web-based conversion service at www2.futureware.at/KiCad that accepts zipped .PcbDoc and .SchDoc files and returns converted KiCad projects.

Both approaches require ASCII format .PcbDoc files for best results, so always save an ASCII copy before attempting conversion.

Creating and Working with .PcbDoc Files

For engineers designing in Altium, understanding .PcbDoc file management improves workflow efficiency.

Creating a New .PcbDoc File

In Altium Designer, new PCB documents are created within project context:

1. Right-click on your project (.PrjPcb) in the Projects panel
2. Select Add New to Project > PCB
3. A blank PCB document opens as “PCB1.PcbDoc”
4. Right-click the document entry and select Save As
5. Enter your desired filename and save

The new .PcbDoc file automatically links to your project, enabling schematic-to-PCB synchronization through Engineering Change Orders (ECOs).

Transferring Schematic Data to .PcbDoc

The connection between schematic (.SchDoc) and PCB (.PcbDoc) files distinguishes Altium from simpler tools. To transfer design data:

1. Complete your schematic design
2. Open the .PcbDoc file (or create one)
3. From the schematic, select Design > Update PCB Document [filename]
4. Review the Engineering Change Order list
5. Click Validate Changes then Execute Changes

Altium transfers component footprints, net connectivity, and design parameters—no intermediate netlist files required.

Version Control Considerations

For teams using version control systems like Git, .PcbDoc file management requires thought:

Many teams maintain binary files for daily work and generate ASCII snapshots at major milestones for meaningful version tracking.

Read more PCB Files format:

What are .GBR and .PHO Files? Gerber File Extensions Guide

What are PCB Panelization Files? Complete Array Format Guide

What is .DSN File? Specctra Autorouter Format Explained

What is .kicad_pcb? KiCad PCB File Format Guide

What is .PcbDoc? Altium Designer PCB Format Explained

What is .PrjPcb? Altium Designer Project File Explained

What is .SchDoc? Altium Schematic File Explained

What is a .ASC File? PADS ASCII Format Explained

What is a .BRD File? Eagle PCB File Format Explained

What is a .DRC File? Design Rule Check Reports Explained

What is a .PCB File? Complete Protel/Altium PCB Format Guide

What is a .SES File? Complete Specctra Session File Guide for PCB Engineers

What is a BOM File? Bill of Materials Format for PCB Assembly

What is a CPL File? SMT Component Placement Guide

What is a Fabrication Drawing? PCB Fab Notes Explained

What is a Gerber Job File? Project Metadata Explained

What is a Netlist? PCB Connectivity Data Explained

What is a Pick and Place File? SMT Centroid Data Guide

What is a Stencil Gerber File? Complete Solder Paste Stencil Guide

What is an Aperture File? Gerber Tool Definition Guide

What is an Assembly Drawing? Complete PCB Assembly Documentation Guide

What is DXF in PCB Design? CAD Drawing Exchange Format Explained

What is Excellon? NC Drill File Format for PCB Manufacturing

What is GenCAD? Universal PCB Data Format Explained

What is Gerber RS-274X? The PCB Industry Standard Explained

What is Gerber X2? The Modern Gerber Format Guide

What is Gerber X3? Component Data in Gerber Files

What is HPGL? PCB Plotter File Format Guide

What is IGES? 3D PCB Model Format Explained

What is ODB++? Complete PCB Data Exchange Format Guide

What is PDF/A for PCB? Documentation Standards Guide

What is STEP File in PCB Design? 3D Model Exchange Guide

What is VRML in PCB? 3D Visualization Format Guide

Useful Resources for Working with .PcbDoc Files

Having the right tools and references available streamlines .PcbDoc file work.

Official Altium Documentation

Conversion and Import Tools

Community Forums

Best Practices for .PcbDoc File Management

Professional workflows benefit from consistent file management practices.

Project Organization

Keep .PcbDoc files with related project assets:

ProjectName/├── ProjectName.PrjPcb├── ProjectName.SchDoc├── ProjectName.PcbDoc├── Libraries/│   ├── Components.IntLib│   └── Footprints.PcbLib├── Output/│   ├── Gerber/│   └── Assembly/└── Documentation/

Backup Strategy

Protect valuable design work with multiple backup layers:

Sharing .PcbDoc Files

When sharing .PcbDoc files externally:

1. With Altium users: Share the native .PcbDoc directly
2. With other EDA users: Save ASCII copy plus Gerber output
3. With manufacturers: Export Gerber/ODB++ (not .PcbDoc)
4. For review only: Use Altium 365 Viewer sharing links

Never send .PcbDoc files directly to PCB manufacturers unless they specifically request native Altium files—always provide standard manufacturing outputs.

Frequently Asked Questions About .PcbDoc Files

What software can open .PcbDoc files for free?

The Altium 365 Viewer provides free browser-based viewing of .PcbDoc files without requiring software installation or account creation. For editing capabilities, KiCad (free, open-source) can import .PcbDoc files starting from version 7, though some conversion artifacts may require cleanup. CircuitMaker, Altium’s free community tool, also opens .PcbDoc files with certain limitations.

How do I convert .PcbDoc to Gerber files?

In Altium Designer, open your .PcbDoc file and navigate to File > Fabrication Outputs > Gerber Files. Configure the layers, units, and format settings in the dialog, then click OK. Repeat the process for NC Drill Files to generate complete manufacturing data. Always verify generated Gerbers in a viewer (like the built-in CAMtastic or external tools) before sending to fabrication.

Can KiCad open Altium .PcbDoc files directly?

Yes, starting with KiCad 7 (released 2023), direct import of .PcbDoc files is supported through File > Import Non-KiCad Board File > Altium Designer PCB. KiCad 9 and later versions provide improved import fidelity. For best results, save your Altium design as ASCII format .PcbDoc before importing, as this improves conversion accuracy for complex designs.

What’s the difference between .PcbDoc and .SchDoc files?

The .PcbDoc extension identifies PCB layout files containing the physical board design—copper traces, component footprints, drill holes, and manufacturing data. The .SchDoc extension identifies schematic files containing the circuit design—component symbols, wire connections, and electrical relationships. Both file types work together within an Altium project, with the schematic driving the PCB layout through synchronization.

Should I send .PcbDoc files to my PCB manufacturer?

Generally, no. Most PCB manufacturers expect Gerber files (RS-274X format) or ODB++ packages, which are universal manufacturing formats that any fabrication house can process. Sending .PcbDoc files requires your manufacturer to have Altium Designer, limits their ability to use standard CAM processes, and potentially exposes your design IP. Always generate and send appropriate manufacturing outputs unless your manufacturer specifically requests native files.

Conclusion

The .PcbDoc file format represents the current state of professional PCB design storage, offering comprehensive data management that goes far beyond simple layer imaging. Whether you’re working natively in Altium Designer, converting designs from other platforms, or preparing files for manufacturing, understanding .PcbDoc files is fundamental knowledge for modern PCB engineers.

The format’s continued evolution—with additions like enhanced 3D integration, cloud collaboration through Altium 365, and improved import/export capabilities—ensures .PcbDoc will remain central to professional PCB design workflows for the foreseeable future.

For engineers using other tools, the growing ecosystem of converters and the native import support in KiCad means .PcbDoc files are more accessible than ever, even without an Altium license. And for manufacturing output, Altium’s robust export capabilities ensure your .PcbDoc designs translate cleanly to whatever format your fabricator requires.

Whatever your workflow, investing time in understanding .PcbDoc file management pays dividends in efficiency, collaboration, and design quality throughout every project.