What Files Do You Need to Order a PCB? Complete File Preparation Guide

"Just upload your Gerber file" sounds simple until you're staring at a KiCad or Altium project folder wondering which of the dozen files in there is actually the one a manufacturer needs. The PCB project file you've been working in isn't the manufacturing file — and sending the wrong thing, or an incomplete set, is one of the most common reasons a first PCB order stalls before it ever reaches the production floor.

This guide breaks down exactly which files a fabrication or assembly order requires, what each one actually contains, how to generate them from the design tools people use most, and how to check them before you upload anything.

The Core Files Every Bare-Board Order Needs

Gerber Files

A Gerber file is a vector-format drawing that describes exactly one layer of your board — a copper layer, a solder mask layer, a silkscreen layer, and so on. A manufacturer doesn't work from a single file; they work from a complete set, and a “complete set” depends on your layer count and finish requirements. For a standard two-layer board, that typically means:

• Top and bottom copper layers, plus internal copper layers for anything beyond two layers.

• Top and bottom solder mask layers, which define where copper is exposed versus covered.

• Top and bottom silkscreen layers, for reference designators, labels, and logos.

• Top and bottom paste layers, needed if you also want a stencil for assembly, not just the bare board.

• A board outline / mechanical layer (often called Edge.Cuts, GKO, or GM1 depending on the tool) that defines the physical shape and dimensions of the board. This is the single most commonly missing file, and without it a manufacturer has to guess your board's outline from the other layers.

The RS-274X standard is what almost every fab expects by default — it embeds aperture data directly in the file so nothing gets lost in translation. Some tools now offer an extended X2 or X3 format that bundles in layer and component metadata; it's increasingly supported, but it's worth confirming your manufacturer reads it before relying on it exclusively.

Drill Files

Hole locations and sizes live in a separate file from your Gerbers, almost always in Excellon (NC drill) format. This file tells the manufacturer where to drill and how large each hole should be, and typically distinguishes plated (PTH) holes — vias, through-hole component leads — from non-plated (NPTH) holes like mounting holes.

Two details matter more than people expect here: the coordinate precision (commonly 2:4 for inches) needs to match what your fab's system expects, and if your design has both plated and non-plated holes, it's worth explicitly checking the “combine PTH and NPTH in a single file” setting in your export tool — leaving it unset is a common way for one of the two to get silently omitted.

Extra Files Needed for PCB Assembly Orders

If you're ordering a bare board only, Gerbers and a drill file are enough. If you want the board populated with components (PCBA), you'll also need:

Bill of Materials (BOM)

The BOM lists every component on your board: reference designator, manufacturer part number, manufacturer name, quantity, and package/footprint. The single most common gap here is a missing or incorrect manufacturer part number — without it, an assembly house has to guess which exact part you meant among several similar ones, which slows the quote and increases the chance of a substitution you didn't intend. If a part has known acceptable substitutes, noting them directly in the BOM saves a support email later.

Pick-and-Place / Centroid (CPL) File

This file tells the assembly line exactly where each component goes: reference designator, X/Y coordinates, rotation, and which side of the board (top or bottom) it belongs on. Rotation is the detail most likely to cause a silent defect rather than an obvious error — if your rotation reference doesn't match the convention your assembly house's equipment expects, polarized parts (diodes, electrolytic capacitors, ICs) can be placed 90 or 180 degrees off without triggering any file-level error. It's worth flagging any non-standard footprints or rotations in your order notes rather than assuming the file speaks for itself.

Exporting These Files from Common Design Tools

The exact menu names shift slightly between versions, but the general path is consistent across the major tools:

• KiCad: File → Plot, select Gerber as the format and choose your layers, then use the Generate Drill Files button in the same dialog for the Excellon output.

• Altium Designer: File → Fabrication Outputs → Gerber Files for the layer export, then File → Fabrication Outputs → NC Drill Files for the drill data.

• Eagle: File → CAM Processor, which runs job files that control exactly which layers get exported and in what format.

• OrCAD / Cadence Allegro: Manufacture → Artwork to configure and generate layer-by-layer output, with drill data generated separately.

Whichever tool you use, run its design rule check (DRC) before exporting anything. Catching a clearance or connectivity issue in your CAD tool takes minutes; catching the same issue after it's already inside a Gerber file — or worse, after a board is fabricated — takes considerably longer.

Other File Formats You Might See Mentioned

A few manufacturers accept native CAD project files directly — Eagle, Altium, and PADs files are the most common — and will convert them to Gerber internally, usually asking you to confirm the converted output before production starts. This can be a convenient shortcut, but it does add a confirmation step to your timeline, so factor that in if you're on a tight schedule.

You may also come across ODB++ and IPC-2581 — both are all-in-one formats designed to bundle fabrication and assembly data into a single dataset instead of a folder of separate Gerber, drill, and BOM files. They're gaining adoption, particularly for complex or high-layer-count boards, but support varies by manufacturer. If you're considering either, it's worth confirming directly with your fab before switching your workflow over.

Naming and Packaging Your Files Before Upload

• Zip everything together — Gerbers, drill files, and (for assembly) BOM and CPL files should travel as one archive, not split across separate uploads.

• Keep layer names unambiguous — if your tool's default output uses generic names, a quick rename (or a short readme) noting which file is which prevents a manufacturer from having to guess, especially on non-standard stack-ups.

• Don't substitute the CAD project file for the export — a .kicad_pcb or .brd file is not the same thing as an exported Gerber set unless your specific manufacturer has explicitly said they accept native files.

How to Verify Your Files Before You Submit

Before uploading anything, run your zip through a Gerber viewer. Check three things specifically: that the board outline is present and matches your intended dimensions, that drill holes line up with pads rather than floating in empty copper, and that your layer count in the viewer matches what you're about to pay for. This single check catches the large majority of file-related order delays before they happen.

Common File Mistakes That Delay a PCB Order

• Missing board outline layer, leaving the manufacturer to infer your board shape from other layers.

• Drill file left out or exported at a mismatched precision, so hole sizes don't line up with the Gerber data.

• BOM without manufacturer part numbers, forcing manual part lookups and slowing the assembly quote.

• CPL rotation that doesn't match the assembly house's convention, risking silent placement errors on polarized parts.

• Sending the CAD project file instead of an exported Gerber set, assuming it's interchangeable when the manufacturer expects standard manufacturing files.

• Skipping DRC before export, so a design-rule violation only surfaces once it's already inside the Gerber data.

Where PCBgogo Fits Into This

Even a carefully exported file set benefits from a second set of eyes before it goes into production, which is why every order that comes through PCBgogo goes through an engineer review rather than being fabricated exactly as uploaded. PCBgogo accepts standard Gerber (RS-274X) and Excellon drill files, and also takes native Eagle, Altium, and PADs files directly, converting them and confirming the result with you before anything is built.

If you want to double-check your files before committing to an order, PCBgogo's free online Gerber viewer lets you open your zip and inspect layers, outline, and drill alignment the same way an engineer would — worth running through before you upload, whether you order from PCBgogo or anywhere else.

FAQ

Do I need Gerber files, or can I send my native design file instead?

Gerber plus a drill file is the most universally accepted option. Some manufacturers, including PCBgogo, also accept native Eagle, Altium, or PADs files and convert them, but they'll typically ask you to confirm the converted result before production.

What's the difference between a Gerber file and a drill file?

Gerber files describe copper, solder mask, silkscreen, and outline layers. The drill file is a separate Excellon-format file that defines hole locations and sizes — it's not part of the Gerber set itself.

Do I need a BOM if I'm only ordering bare boards?

No. A BOM and pick-and-place file are only required for assembly (PCBA) orders. Bare-board fabrication only needs Gerber and drill files.

What format should my drill file be in?

Excellon (NC drill) format is the standard almost every manufacturer expects, with precision and units matching your Gerber export settings.

What happens if my Gerber files are missing a layer?

A thorough engineer review should catch it and contact you before production, but it's faster and safer to check your file set yourself in a Gerber viewer before submitting.

Is ODB++ or IPC-2581 better than standard Gerber files?

They bundle more data into a single file and are gaining adoption for complex boards, but support isn't universal. Standard Gerber plus drill files remains the safest default unless your manufacturer confirms otherwise.