Free online Gerber viewer
Online Gerber Viewer: Free Gerber File Viewer in Your Browser
Drag in RS-274X Gerbers and Excellon drill files, or a ZIP, to preview every layer, check for missing files and measure board size. Nothing is uploaded.
Gerber viewer
Gerber file viewer.
Board extents: —
Preview only. Aperture macros and some advanced commands may not render. Your files are parsed locally and never uploaded. For a full engineering check, upload to quote.
What to check
What to check in a Gerber viewer.
- Every copper layer present and aligned
- Drill hits land on pads on all layers
- Solder mask openings expose pads, not traces; dams ≥ 3 mil
- Silkscreen readable and off pads
- Board outline matches the mechanical drawing
- Drill sizes match the via/hole plan
Common errors
Common Gerber export errors.
| Error | Symptom |
|---|---|
| Missing layer | No inner layers, paste or mask in the set |
| Wrong units / format | Board appears 25.4× too big or small |
| Offset drill file | Holes shifted from pads |
| Outline on copper layer | Board edge drawn as a copper trace |
| Negative plane misread | Planes appear inverted |
Workflow
A pre-fabrication checking workflow.
- 01
Export
Gerber RS-274X/X2 and Excellon from your EDA tool.
- 02
Load
Drop the files or ZIP into the viewer.
- 03
Check
Layers present, aligned, outline correct, drills on pads.
- 04
Upload
Send to quote for engineering DFM.
Most fabrication delays come from export mistakes, not design errors: a missing layer, wrong units, an offset drill file or an outline drawn on copper. A two-minute check in a viewer catches most of them before the files reach CAM.
Layer naming
Common Gerber file extensions.
| Extension | Layer |
|---|---|
| .GTL / .GBL | Top / bottom copper |
| .G2, .G3 … / In1_Cu | Inner copper layers |
| .GTS / .GBS | Top / bottom solder mask |
| .GTO / .GBO | Top / bottom silkscreen |
| .GTP / .GBP | Top / bottom paste |
| .GKO / .GM1 / Edge_Cuts | Board outline |
| .DRL / .XLN | Excellon drill |
If a layer is misidentified, rename it with a standard extension and reload. Mixed naming is common when files come from different tools.
Gerber X2 & ODB++
Gerber X2, ODB++ and IPC-2581.
Gerber X2 adds file attributes (layer function, polarity, pad roles) that remove ambiguity in CAM. ODB++ and IPC-2581 carry the whole job in one structured file, including stack-up and netlist. All three are accepted for fabrication. The viewer previews RS-274X and X2 Gerbers with Excellon drill. For ODB++ or IPC-2581, upload directly to quote.
Quick checks
Five checks before you upload.
- Layer count in the viewer matches your stack-up
- Board extents match the mechanical drawing
- Drill hits land on pads on every copper layer
- Solder mask openings exist on every pad (and not on vias you want tented)
- Outline is a single closed shape on its own layer
If any check fails, re-export from your EDA tool. It is faster than explaining the file set to CAM later.
File formats
Supported file formats.
The viewer reads RS-274X (extended Gerber) and Excellon drill files, individually or in a ZIP. For fabrication we also accept Gerber X2, ODB++ and IPC-2581. Read more about our free DFM review.
FAQ
Tool questions.
Is this Gerber viewer free?
Yes, free and browser-based with no sign-up.
Are my files uploaded?
No. Files are parsed locally in your browser and never leave your computer.
Which files can I open?
RS-274X Gerber and Excellon drill files, individually or as a ZIP.
Can it replace a DFM check?
No. It is a visual preview; our engineers’ DFM review checks manufacturability in depth.
Why does my board look 25× too big?
Units or format mismatch between Gerber and drill files; re-export with consistent units and format.
Which layers should a fabrication set include?
All copper layers, solder mask and silkscreen for both sides, board outline, drill files and a fabrication drawing or README.
Ready when your files are
Done designing? Get it built.
Upload Gerber, ODB++ or IPC-2581 data. Every quote includes a written engineering DFM review, typically within one business day.