How to open and check Gerber files before you order
A Gerber set is a folder of plain files. Here is how to view it, what to check on each layer and how to export a clean set from KiCad.
Why check the files yourself
Your PCB manufacturer works from exactly the files you send, not from your CAD project. A wrong export means a wrong board. Checking the set in a viewer takes a few minutes and shows what the factory will see.
Ways to open Gerber files
- The Gerber viewer of your CAD program. KiCad includes one (GerbView); other CAD suites have an equivalent.
- A free desktop viewer. Several exist — choose one that reads RS-274X Gerber and Excellon drill files.
- An online viewer. Quick for a first look, but you upload your design to a third party, so use it only for non-confidential boards.
- The PCB-ELECTRA price calculator. Upload the ZIP or RAR archive and it shows a preview of the board with the detected layer count and size. Uploaded files are treated as confidential.
A Gerber file is plain text, but its geometry only makes sense in a viewer — do not try to judge it in a text editor.
What to check, layer by layer
| Layer | What to check |
|---|---|
| Board outline | Closed shape, correct dimensions, cut-outs and slots present |
| Copper | Traces and pads as designed, no copper too close to the edge, inner layers present on 4- and 6-layer boards |
| Solder mask | Openings sit exactly on the pads, no unwanted openings over traces |
| Silkscreen | Not over pads, text readable and not too small |
| Drill | Holes centred on the pads, plated and non-plated holes separate, plausible sizes |
Also confirm that all layers share the same origin and that the board size matches your design.
Step by step: exporting from KiCad
- Run the design-rule check (DRC) and fix the errors.
- Open File → Plot and choose the output format Gerber and an output folder.
- Select the copper layers, F/B Mask, F/B Silkscreen and Edge.Cuts.
- Optionally enable the Protel file extensions if you prefer the .GTL / .GBL naming.
- Click Plot, then Generate Drill Files: Excellon format, millimetres, plated and non-plated holes in separate files.
- Open the folder in the Gerber viewer, check it as above and pack everything into one ZIP archive.
Typical findings in the viewer
- Holes missing: the drill files were not loaded in the viewer — load the .DRL files as well.
- Pads and holes do not line up: the files come from different exports or origins — export everything again in one run.
- Outline open or doubled: join or clean the outline segments in your CAD program.
- Silkscreen over pads: move the text; it will not print on bare copper.
Then send the files
Pack the checked set into one archive and upload it in the price calculator. The background on file types and common mistakes is in our Gerber guide.
Frequently asked questions
Which program can open Gerber files?
Any Gerber viewer works, including free ones such as the Gerber viewer of KiCad or gerbv. Open all files together, so that you see the board the way it will be manufactured.
What should I look for when I check the files?
That every layer is present, that the outline is closed, that the drill holes sit in the centre of the pads and that the solder mask openings match the pads.
Is the preview in your calculator enough as a check?
It is a quick check that the archive is complete and readable. Our engineers also review every file before production and contact you if something is unclear.
Browse the questions and answers →
Upload your files and see the price
Add your Gerber files in the calculator: you see the board, the options and an instant price in euros.
Upload files in the calculator →Ask an engineer
Not sure what applies to your board? Describe it in a few lines and our engineers will advise you.