Every printed circuit board starts its factory life as a set of files, not as a board. Your EDA tool exports those files, the board house reads them, and between the two sits the most valuable ten minutes in the whole process: opening the exported set in an independent viewer and looking at what will actually be built. Gerbv exists for exactly that job. It is a free, open-source viewer (GPL-2.0-or-later, originally part of the gEDA project) for Gerber RS-274X files, Excellon drill files and CSV pick-and-place files, and it runs on Windows, macOS and Linux. This tutorial walks through the complete first session: getting the files out of the fabrication ZIP, opening them so they stack into a board, moving around the view, and understanding what each file in the set is. If Gerbv is not installed yet, start with the Windows installation guide and the files on the download page; the broader picture of what a viewer does is on our Gerber viewer page.
Step 1: Extract the fabrication ZIP — and keep the set together
Board houses and EDA export presets almost always deliver fabrication data as a single ZIP archive. Extract the whole archive into its own folder before opening anything, and keep that folder intact. A Gerber set only makes sense as a set: each file describes one layer or one kind of data, positioned in the same coordinate space as all the others, and viewing one file in isolation tells you very little. Resist the urge to rename files at this stage, too. Filenames carry the layer information — which file is top copper, which is the solder mask — and while Gerbv detects file types from their content when it loads a folder, clear names remain your own map of the set. If the set came from someone else, extracting it unchanged also preserves the evidence of exactly what was sent.
Step 2: Know what each file type is before you open it
A typical export contains three kinds of data, and Gerbv opens all three. Gerber files (RS-274X) describe the artwork layers: top and bottom copper, any inner copper layers, solder mask, silkscreen, solder paste and usually the board outline. Each Gerber file is one layer — there is no single “board file”. Drill data is separate: an Excellon (NC drill) file lists the drill tools and the position of every hole. Assembly positions are separate again: a CSV pick-and-place (centroid) file lists where components sit on the board. Our explainer What is a Gerber file? covers the format and the layer set in depth. One warning that saves real confusion: file extensions are not reliable. Tools use .gbr, .ger, layer-specific suffixes and various naming patterns, so judge a file by loading it and by the export notes, not by its name alone. Legacy RS-274D files are the one Gerber variant Gerbv does not support — modern tools export RS-274X, so choose that format if your EDA tool offers a choice.
Step 3: Open the layers so they stack into a board
Launch Gerbv and open your files from the main window. You can open files one at a time, building the stack yourself, or point Gerbv at the extracted folder: the documented behaviour is that opening a directory loads all the loadable files it finds — detected by content, in alphabetical order, without descending into subfolders. Either way, the result is a layer list beside the drawing area, with every file stacked in registration on the same canvas. Load the copper layers first, then the mask and silkscreen, then the Excellon drill file on top, following the workflow in loading and aligning Gerber layers. Each layer can be shown or hidden, so you can peel the board apart visually: copper alone, copper plus mask, everything plus drills. Right-clicking a layer in the list gives per-layer operations such as reloading the file or changing its colour — set colours you can tell apart, because the next steps are all about comparing layers against each other.
Step 4: Zoom and pan — learn to move before you judge
A freshly loaded board usually appears fitted to the window, which is the right place to start: does the outline look like your board, are the dense areas where you expect them, is anything obviously floating outside the outline? From there, viewing is a rhythm of zooming in to inspect detail and pulling back out to keep your bearings. Zoom into a connector footprint and look at the individual pads. Pan along a bus of traces and watch whether they run where the design says they should. Zoom into the corners and read the silkscreen text — is it the right way up, complete, and clear of the pads it labels? Take the same tour with only the drill layer visible over the copper, which is the subject of viewing Excellon drill files: every hole should land in the middle of a pad or via, not beside one. None of this needs any special technique — it needs the habit of actually looking, at full magnification, at the exported files rather than at the design view in your EDA tool, which shows intent instead of output.
Step 5: A first-session checklist
Before closing that first session, run through the short version of the pre-order check. Count the layers against the export list — a missing file is the most common export accident, and it is invisible until you notice a layer that should exist does not. Confirm the board outline is closed and the size looks right; the measurement guide shows how to verify it numerically. Toggle the solder mask over the copper and confirm pads are opened and traces are covered. Add the pick-and-place file if you have one — viewing pick-and-place files covers that overlay — and confirm component positions sit inside the outline. Finally, remember what Gerbv is and is not doing here: it shows and measures the fabrication data, and its report windows summarise the Gerber and drill codes in use, but it does not run design-rule or DFM checks and it is 2D only. The visual pass is yours to make, and it catches the mirrored, stale and incomplete exports that no automated summary can.
Frequently asked questions
Which files should I open first in Gerbv?
Start with the copper layers, then add the solder mask and silkscreen, and finish with the Excellon drill file stacked on top. Opening the extracted folder loads all loadable files at once, in alphabetical order, detected by content.
Can Gerbv open the ZIP file directly?
Extract the fabrication ZIP into its own folder first, then open the files — or the folder — from Gerbv’s main window. Keeping the extracted set together and unchanged also preserves exactly what was exported or sent.
What if one of my files will not open?
Check the format first: Gerbv views Gerber RS-274X, Excellon drill and CSV pick-and-place files, and legacy RS-274D is explicitly not supported. If your EDA tool offers a format choice, re-export as RS-274X.