The Slimline Envelope is sized at 4" x 9" when assembled Due to the size of the envelope as it comes,  it is recommended for 12” x 12”+ cutting mats.  If you are using a Portrait (8' x 12") cutting area you will have to reduce the size of the envelope to cut.  Look for the coordinating Slimline Pop-Up Cards!  See more on my blog: Slimline Envelope