Gerber files for PCB manufacturing: what to send and how to export
A practical checklist for engineers: which files a manufacturer needs, how to export them from KiCad, Altium or EAGLE, and which mistakes delay an order.
What a Gerber file is
Gerber (RS-274X, also called Extended Gerber) is the standard vector format in which a PCB design is handed over to a manufacturer. Every layer of the board — copper, solder mask, silkscreen, board outline — is its own file. Drill data travels separately in an Excellon (NC drill) file. The newer Gerber X2 format adds layer information to the files, but you still send one file per layer.
Which files to send
| Layer | Typical extension | Needed? |
|---|---|---|
| Top copper | .GTL | Yes |
| Bottom copper | .GBL | Yes, from 2 layers |
| Inner copper layers | .G1, .G2 … | Yes, for 4 and 6 layers |
| Solder mask top / bottom | .GTS / .GBS | Yes |
| Silkscreen top / bottom | .GTO / .GBO | Yes, if the board has a legend |
| Board outline | .GKO, .GM1 or Edge.Cuts | Yes — without it the board shape is unknown |
| Drill file (plated and non-plated) | .DRL, .XLN or .TXT | Yes |
| Solder paste | .GTP / .GBP | Only for SMD stencils, not for the bare board |
Extensions differ between CAD programs. What matters is one file per layer with a clear name.
Exporting from your CAD program
- KiCad: File → Plot. Select all copper layers, F/B Mask, F/B Silkscreen and Edge.Cuts, choose Gerber format and millimetres. Then use Generate Drill Files (Excellon, millimetres, plated and non-plated holes in separate files).
- Altium Designer: File → Fabrication Outputs → Gerber Files and NC Drill Files. Make sure the board outline (keep-out or mechanical layer) is part of the output.
- EAGLE: CAM Processor with the Gerber RS-274X job, plus the Excellon job for the drill data.
Mistakes that delay an order
- No board outline, or an outline made of unconnected line segments.
- Drill file and Gerber files from different exports (different origin or units).
- Plated and non-plated holes mixed in one drill file without being marked.
- Silkscreen over solder pads, or text so small that it will not print legibly.
- Copper too close to the board edge or to drilled holes; traces narrower than the manufacturer’s minimum.
- Inner layers missing on 4- and 6-layer boards, or layers in the wrong order.
- Slots and cut-outs drawn on a copper layer instead of the outline layer.
Check before you send
Open the complete set in a Gerber viewer (the one built into KiCad or any online viewer) and check that the outline is closed, the holes sit on the pads and all layers share the same origin. Five minutes here can save days.
Sending the files to PCB-ELECTRA
Pack all Gerber and drill files into one ZIP or RAR archive and upload it in the price calculator. The calculator reads the archive, shows a preview of the board and detects layer count and size — a first plausibility check. Our engineers still verify every file before production and contact you if something is unclear. We also accept PDF, Eagle and KiCad project files, but Gerber files give the most reliable result. All uploaded files are treated as confidential.
Production starts from 1 piece: the standard lead time is 9 working days for 1- and 2-layer and aluminium boards (4- and 6-layer boards take longer), and urgent production is available — the calculator shows the delivery date for your configuration. Technical limits are listed under capabilities.
Frequently asked questions
Which files do I need to send?
One Gerber file for every copper layer, the solder mask layers, the silkscreen layers and the board outline, plus the Excellon drill files. Put everything in one ZIP or RAR archive.
In which units and format should the drill file be?
Excellon format in millimetres, with plated and non-plated holes in separate files, and the same origin as the Gerber files.
Can I check my files before ordering?
Yes. The price calculator reads your archive, shows a preview of the board and detects the layer count and the dimensions, so you can spot a missing layer immediately.
Browse the questions and answers →
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