PCB size 0.2mm smaller after export


My PCB turns out to be approximately 0.2mm shorter in both directions after I export it as a Gerber file. Anybody knows why? I’m making a Eurorack module and a 95x66 mm PCB ends up being 94.79x65.79 mm after export.


Upload the sketch (the .fzz file, upload is 7th icon from the left in the reply menu) and one of us will have a look at it. Without the sketch not much can be said except it shouldn’t happen.


Please check the following file:

It looks correct to me. This is the gerber displayed in gerbv:

and the board appears to be very close to 66mm by 95mm with the cursor on the outside edges of the rectangle. Is the result you are getting different? I will admit I have never before had occasion to measure the size of a board so I could be missing something here. This is from Fritzing 1.0 on Win10.


Yes it’s different. I uploaded the gerber file to two PCB manufacturers and both of them show the following:

jlcpcb.com: “Detected 2 layer board of 94.79x65.79mm”
aisler.net: “Dimension / Size 65.79mm x 94.79mm”

Any ideas? I’m on version 0.9.10 but searching for updates give “No updates”

Just talked to JLCPCB and they said that if the outline is thicker than 0.15 mm they will calculate the width from the center of the outline, which explains the discrepancy. So a suggestion would be to add the possibility to change how thick the PCB outline in Fritzing should be :slight_smile:

Thanks for reporting this.
There is a open issue in the bug tracker. I copied/pasted your message there.

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