Gerber Viewer
Inspect your PCB layers. File previews run in your browser. Selected files are uploaded only when you submit an engineering inquiry.
- 01Open your board
- 02Inspect PCB layers
- 03Engineering inquiry
Practice with the Gerber layer checks teaching pack: compare an original export, a missing outline and misleading layer names.
Exporting from KiCad? Check the KiCad BOM and placement export compatibility notes before you send fabrication and assembly files.
Drop files here. Gerber / Excellon / Altium / KiCad 6–7 / EAGLE XML · KiCad up to 8 MB, other files 4 MB · 32 MB total.
Preparing the local viewer. If controls remain unavailable, reload this page.
Experimental native PCB previews. KiCad 6/7 sample formats verified; other versions are not enabled. EAGLE XML shows geometry, not repoured copper. Verify manufacturing data in PCB/CAM software.
How to use the online Gerber viewer
- Click Open files or ZIP and choose your Gerber export, or drag the files onto the viewer. You can also load the sample board to try it first.
- Toggle individual layers to check copper, solder mask, silkscreen, paste and drill alignment.
- Switch to 3D bare board view and set the preview thickness to check the outline and overall shape.
Supported file formats
The viewer opens Gerber (RS-274X) and Excellon drill files, Altium exports, KiCad 6–7 files and EAGLE XML. Previews are processed in your browser. Selected files are uploaded only when you submit an engineering inquiry. Size limits are 8 MB for KiCad files, 4 MB for other single files and 32 MB in total.
What to check before sending files to a PCB assembler
- Board outline: a missing or open outline layer is one of the most common reasons a quotation is delayed.
- Layer names and order: make sure top and bottom layers are clearly identified and the stack-up matches your design.
- Drill files: confirm plated and non-plated holes line up with the copper pads.
- Paste layer: check that fine-pitch and BGA pads have paste openings, since this affects SMT stencil design.
The viewer is a quick visual check, not a CAM tool, so always verify manufacturing data in your PCB/CAM software. When your files look right, send them with your PCBA RFQ or review the RFQ checklist.
Gerber file FAQ
What is the difference between RS-274X and RS-274D Gerber files?
RS-274X (Extended Gerber) embeds the aperture definitions inside each layer file, so a viewer can draw it on its own. RS-274D is the older standard-Gerber format that needs a separate aperture list; most viewers, including this one, do not accept it. Export RS-274X or Gerber X2 from your CAD tool.
What does Gerber X2 add?
X2 keeps RS-274X compatibility and adds file attributes that state what each file is: layer function, side, polarity and project. A viewer or CAM tool can map layers from those attributes instead of guessing from filenames. KiCad, Altium and EAGLE can all export X2; the Gerber layer checks teaching pack shows what happens when filenames and attributes disagree.
Why isn't my drill file showing?
Drill data is not Gerber. It is usually an Excellon file (.drl, .xln, .txt or .exc). Check that the drill file was exported, that it is in the same upload, and that its units and zero suppression match the CAD export settings. If the holes land in the wrong place, the drill and copper files were exported with different origins or units.
Which layer file extension is which?
Common conventions: .gtl / .gbl top and bottom copper, .gts / .gbs solder mask, .gto / .gbo silkscreen, .gtp / .gbp paste, .gm1 or .gko board outline, .g2 / .g3 inner layers. KiCad uses descriptive names such as -F_Cu.gbr. Extensions are only a convention; the X2 attributes or the job file (.gbrjob) are the reliable source.
Can I check a board with only Gerber files?
You can check geometry: layer alignment, outline, mask openings and silkscreen clearance. Gerber files carry no netlist, so they cannot confirm connectivity. For that, export IPC-356 netlist data alongside the Gerbers, or review the design in its native CAD format.