How to Open a .pcb File — Which Program Made It and What Opens It
One Extension, a Dozen Formats
A .pcb file is not one format. PADS, Protel, P-CAD, DesignSpark PCB, Easy-PC, gEDA, CADSTAR, Pulsonix, ExpressPCB and old DOS tools all save boards as .pcb, each in its own format — some text, most binary. That is why a .pcb that opens on one machine says "unknown file" on another. The first step is finding out which program made it.
The Quick Way
Drop the file on MakerSuite 3D. It reads the first bytes, opens the kinds it can read, and for the rest tells you which program made the file and what to do — the same answers as the table below. Nothing is uploaded.
Drop your .pcb file — the viewer tells you which program made it.
Try MakerSuite 3D FreeWhich .pcb Is It?
Open the file in a text editor and look at the first line, or just drop it on the viewer. Binary files show mostly unreadable characters.
| File starts with | Made by | Opens here? | What to do |
|---|---|---|---|
!PADS-POWERPCB-V9.4-MILS! | PADS Layout — ASCII export | ✓ Yes | Opens here directly. |
| binary | PADS Layout — binary database (most binary .pcb files) | No | In PADS Layout use File > Export and save as ASCII (.asc), then open that here — the export dialog can also write older ASCII versions. Altium, KiCad 10, Allegro and EasyEDA Pro import the ASCII file, not the binary. Without a PADS seat, Siemens’ free PADS Standard/Plus Viewer opens PADS VX databases for viewing. |
ACCEL_ASCII | P-CAD 200x — ACCEL ASCII | ✓ Yes | Opens here directly. KiCad imports it too. |
|RECORD=Board|KIND=Protel_Advanced_PCB | Protel 99 SE — PCB ASCII | ✓ Yes | Opens here directly. |
PCB 4.0 Binary File … |KIND=Protel_Advanced_PCB| | Protel 99 SE — PCB binary (3.0 / 4.0) | No | Altium Designer imports it. Or, in Protel 99 SE, save the board again in the PCB ASCII format and open that here. |
D0 CF 11 E0 (OLE2) | Protel 99 SE design database, or a Protel DXP board | ✓ Yes | Opens here: the board inside the database is found and read. |
D0 CF 11 E0 + “PCB Design” | DesignSpark PCB / Easy-PC | No | Only those programs read it. Export Gerber and drill files from DesignSpark PCB or Easy-PC and open the .zip here. |
PCB FILE 4 · 5 · 6 | Protel Autotrax / Easytrax (DOS) or Protel for Windows 2.8 — text | No | Altium Designer opens it: save it as .PcbDoc and open that here. pcb-rnd also reads Autotrax and Easytrax boards. No released KiCad imports it. |
PCB["…" …] | gEDA PCB / pcb-rnd — text | No | KiCad 10 imports it (File > Import > Non-KiCad Board File): save as .kicad_pcb and open that here. Or export Gerber files from pcb-rnd. |
| binary | ExpressPCB Classic | No | Only ExpressPCB opens it, and it has no Gerber export: ExpressPCB sends Gerber files only with a board order. ExpressPCB Plus can import Classic files. |
| binary | Zuken CADSTAR | No | Save a PCB archive (.cpa) from CADSTAR — KiCad and Altium import that — or export Gerber files. |
| binary | Pulsonix | No | A native binary format: export Gerber files from Pulsonix and open the .zip here. |
XZZPCB | XZZ boardview (phone and laptop repair) | No | Not a design file but an encrypted board diagram for repair work. Open it in a boardview program. |
Boards That Are Not .pcb
KiCad saves .kicad_pcb, Altium .PcbDoc, Eagle and Cadence Allegro .brd, EasyEDA .json, DipTrace .dip. All of these except DipTrace open here as well.
Why So Many Programs Chose .pcb
Most of these tools date from the 1980s and 1990s, when an extension was three letters and ".pcb" was the obvious choice. Nothing in the name says which program wrote the file — only its content does: a PADS ASCII file starts with !PADS-, P-CAD with ACCEL_ASCII, old Protel with PCB FILE, gEDA with a PCB[ line, and compound files (Protel databases, DesignSpark) with the bytes D0 CF 11 E0.
Binary formats are the hard part: their layouts are private, so other tools can read them only through the original program’s own export. That is why the answer for a binary .pcb is almost always "export ASCII or Gerber from the program that made it".
Frequently Asked Questions
Why won't my .pcb file open?
Because .pcb is used by more than a dozen programs, each with its own format. Find out which program made the file (the table above, or drop it on the viewer). Most binary .pcb files are PADS Layout databases, which tools outside PADS read only through PADS' own ASCII export.
Can I convert a binary PADS .pcb without PADS?
Not directly: Altium, KiCad 10, Allegro and EasyEDA Pro all import the ASCII (.asc) export, not the binary database. Siemens' free PADS Standard/Plus Viewer opens PADS VX databases for viewing. Otherwise ask whoever sent the file for an ASCII export or Gerber files.
Can KiCad open a .pcb file?
Some of them. KiCad imports P-CAD ASCII boards, and since KiCad 10 also PADS ASCII and gEDA/pcb-rnd boards (File > Import > Non-KiCad Board File). No released KiCad imports binary PADS, Protel 99 SE, Autotrax or DesignSpark boards.
Is my file uploaded anywhere?
No. MakerSuite 3D reads the file in your browser; it never leaves your machine.
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