What angle do I cut the trim here?

by Faddu

I have sloped ceiling and I can’t figure out how to cut the trim to go on the top of this bookshelf. I’m not doing crown molding, just a half round type trim. I’ve attached a pic of the angle finder numbers and the sloped ceiling. Thanks!

  9 answers
  • William William on Dec 03, 2021

    Instructions (hopes this helps)



  • Mogie Mogie on Dec 03, 2021


  • Oh math and angles, brain bender for sure, ouch! Looks like your horizontal piece would be 153.5-ish degrees, and your sloped piece at the joint would be about 36.5. Definitely use some scrap pieces to test first!

    • See 2 previous
    • It is like a bevel cut, yes. Mark your angle on the trim with a pencil and then use a fine toothed hand saw, or miter saw, to cut it. You might find it easier to lay it flat to cut but your test pieces should help you figure everything out. I’m cheering you on!

  • Seth Seth on Dec 03, 2021


    You can find youtubes about how to figure angles without a protractor. I like to make a cardboard template that I can adjust in increments until it fits the angle of the sloped ceiling. I then adjust my mitre saw to match the angle and test fit a scrap.

    • See 2 previous
    • Seth Seth on Dec 04, 2021

      A bevel gauge is another inexpensive useful tool for copying angles and transferring them to your work piece.

  • Michelle Leslie Michelle Leslie on Dec 04, 2021

    Hi Faddu, this video has such a simple but awesome trick you can use to figure out that angel. No maths just two pieces of wood - https://www.youtube.com/watch?v=EyVL2ByubVw

  • Annie Annie on Dec 05, 2021

    OK, First the scale to use is the one that is showing about 27 deg. Divide that in half = 13.5. Set your miter saw at 13.5. Cut two scrap pieces and try the fit. Adjust as required.

  • Deb K Deb K on Dec 05, 2021

    Hi Faddu, hope this helps you out,


  • Kathy Gunter Law Kathy Gunter Law on Dec 07, 2021

    I can't really explain it but you should use a compound mitre saw in order to cut both angles at the same time.