Doing a fillet on a corner on a PCB

I have a pcb that has a 45 degree angle on the upper left corner. I would like to round off the corners so they are not so harsh. I use the arc tool all the time to create rounded corners on pcb’s but they are always 90 degree turns. Is there any easy way to do this for a 45 degree angle.

Select the two lines (for example the vertical and the 45 deg in your screenshot → context menu → Fillet Lines


OMG, so easy. KiCad is just amazing. Thank you @eelik


I didn’t know this. Thanks eelik.

It also works on rectangles (drawn with the rectangle tool). Select the rectangle then Fillet Lines. KiCad fillets all four corners.

I didn’t know this context tool either – very handy eelik.

Say, how are people marking posts as “Solution” with the checkmark? That seems new.

yes, recently intoduced discourse feature:

1 Like

I think I will continue to just edit the title with [Solved] as it is immediately apparent. A little green checkmark and note way down in the post seems pretty useless to me.

Also… consider using FreeCAD and the StepUP extension so you can load your PCB into freecad and use its constraints editor to define the board outline.
Its an absolute lifesaver!


The new “solved” marking does more then editing the title.

  1. Just as editing the title, it also shows on the front page ( As a grey checkbox with a mark in it).
  2. It is quicker then editing the title.
  3. The forum software creates a header of the “solution” and attaches it to the first post, so you do not have to read though the entire topic but also know which post is marked as the solution.
  4. The forum software puts up a banner if you add a post to a topic that is already solved:


I noticed the forum software also does this to the user credited with the solution:

Now badges, likes and solutions can be collected :rofl:

Great question @iitgrad and terrific answer/solution, @eelik, thanks!

Just wanted to give a different perspective here, as I have been doing the same sort of thing since KiCAD 5 which probably didn’t have that feature.

The way I would tackle this is to calculate the endpoint of the line using trigonometry and set those coordinates in the line’s properties. Then draw the arc and rely on snapping to the line endpoint to set the arc angle.

Whilst the fillet feature is undoubtedly useful, until KiCAD has a constraint based drawing editor as FreeCAD has, there will probably always be a need for trigonometry if you are doing anything more advanced than just fillets

For example I often need to draw a line that is tangential to a pair of arbitrary circles. There are 4 solutions to such a problem. So I normally just search for a convenient webapp that can solve it. I put the circle centres and radii into the webapp and click “solve” and then copy the coordinates of the line that I want back into KiCAD. Then I can draw arcs using the snapping feature as noted.

Generally for whatever trig problem you may have, you will be able to find a webapp for it. For some unusual ones I instead write a Python script that spits out S-expression data for insertion into my KiCAD PCB file. Happy to share any of my scripts upon request.

Kind regards, Nick