What Is a Gerber File?

"If your design needs controlled impedance, length matching, and production release data, the real threshold is not price but output quality; a tool that cannot generate verified Gerber, drill, and pick-and-place files will cost more than a $300 monthly license."

Hommer Zhao, Founder & CEO, WIRINGO

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.

"For teams designing 6-layer and 8-layer boards, library control and DRC rule coverage matter more than UI polish, because one missed clearance rule can burn a full prototype spin."

Hommer Zhao, Founder & CEO, WIRINGO

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.

"I look for three outputs before I trust any PCB CAD flow: netlist consistency, manufacturing outputs checked against IPC naming conventions, and a 3D review that catches connector interference before release."

Hommer Zhao, Founder & CEO, WIRINGO

If you want to turn this topic into a production decision, review our EDA comparison reference, check the supporting numbers on the EDA shortcuts reference, and use the contact page if you need a second review before release.

FAQ

What features matter most in PCB layout software?

For professional work, the short list is controlled-rule DRC, multi-layer stackup support, 3D clearance review, and manufacturing outputs such as Gerber X2, drill files, and pick-and-place exports.

Is free PCB design software good enough for a real product?

It can be for 2-layer or moderate 4-layer designs, but once the board reaches fine-pitch BGAs, impedance control, or dense library management, commercial tools usually save at least one prototype spin.

How many layers can entry-level tools handle reliably?

Many can draw 4-layer and even 6-layer boards, but the real limit is rule management and verification quality, not the raw layer count shown in marketing.

What file outputs should I verify before sending a board to fabrication?

At minimum, review Gerber or ODB++, NC drill, stackup notes, assembly drawings, and BOM outputs. A missing polarity mark or drill map can delay production by days.

Why is library control such a big deal in EDA tools?

A footprint error of even 0.2 mm can be enough to cause tombstoning, insufficient heel fillet, or connector interference. Centralized libraries reduce that risk across every release.

How should a team compare EDA tools objectively?

Use the same test design, then score routing speed, DRC coverage, library workflow, and manufacturing output accuracy. Three trial builds usually reveal more than a feature checklist.