What Is a Gerber File?

Gerber files are the industry-standard format for communicating PCB designs to manufacturers. Named after Gerber Scientific, who developed the original format, these files contain all the information needed to fabricate a printed circuit board.

Understanding Gerber Format

Gerber files are open ASCII vector format files carrying data on every physical board layer. They use simple commands to describe shapes, lines, and apertures that define the PCB artwork.

Gerber File Formats

RS-274-D is the original format, now largely obsolete. RS-274-X (Extended Gerber) is the current industry standard, embedding aperture definitions within the file. Gerber X2 is the latest version with added metadata for layer functions and attributes.

What Gerber Files Define

A complete Gerber package includes files for: copper layers (top, bottom, inner layers), solder mask layers, silkscreen/legend layers, paste mask for stencils, and board outline. Each layer is a separate file.

Drill Files

Gerber packages also include Excellon drill files (.drl or .xln) specifying hole locations and sizes. These are technically not Gerber format but are always required alongside Gerber files.

Generating Gerber Files

Most PCB design software (Altium Designer, KiCad, Eagle, OrCAD) can export Gerber files. Before sending to manufacturing, verify them using an online Gerber viewer to catch potential errors early.

Common Issues

Frequent problems include missing layers, incorrect aperture settings, missing drill files, and incorrect units (imperial vs metric). Always review your Gerber output before submitting to fabrication.

Best Practices

Include a README file listing all Gerber files and their corresponding layers. Use clear naming conventions. Verify the board outline is on a separate layer. Check that all drill sizes are specified correctly.