Well it seems Inkscape has issue at leas your version?
In the last version, Inkscape returns the same size of KiCAD. I installed it after a talk in GitHub where it was spotted this.
Just kidding, it’s true about the new version but it seems it’s related to DPI. Hence if this is changed, it changes also the size
I wanted to try. Inkscape doesn’t export filled in polygons as Affinity. But sizes are ““correct””
hence I suppose KiCAD is also correct but not Affinity.
So, I opened a topic on Affinity forum … now let’s get insulted even there …
However, wanted or no wanted, sizes are NOT correct and this has issues. And all related DPIs
Somebody will think “why should you use SVGs in a PCB program”.
I tell you: JLCPCB realizes ALUMINUM PCBs which are used to create FRONT and BACK Panels.
What they need, is GERBER Format.
HENCE the only one way to create a front panel under these conditions, is to create a SVG with the correct f…ng size, import it into the not-graphical-friendly-at-all PCBNew, then export the Gerber.
Uploading it to JLCPCB, I get the panel I need: machined and serigraphed.
Hence: there is a valid “because” answering to the “why”, related this need :-/
FYI to get a front panel 165x40 OR 150x110mm machined and serigraphed, it costs around 5.5 Euro included shipping and import taxes to Belgium.
Perhaps it’s time to improve the graphical management of KiCAD … ah no … I forgot that somebody says “it doesn’t serve to me, so we can go back to hieroglyphics”