How To Trim Wallpaper at the Doorway

Press a strip of wallpaper against the wall along the right side, leaving at least two extra inches of the paper to extend into the doorway.

Press the next strip of wallpaper, ensuring that the pattern lines up with the strip you just hung, along the wall between the top of the doorway and the ceiling. Allow at least two inches of wallpaper to hang over the door frame.

Repeat Step 1 on the opposite side of the doorway using a strip of wallpaper that lines up with the pattern you hung in Step 2 near the ceiling. Allow at least two extra inches of the paper to extend into the doorway.

Use a smoothing brush or tool to gently smooth away any air bubbles, wrinkles or excess paste from the wallpaper.

Make a diagonal cut in the wallpaper with the scissors at the four corners of the doorway, stopping at each of the corners of the door frame. The cut will likely be about two inches, depending on the amount of excess wallpaper you allowed for when hanging.

Press the trim guide at the top right of the doorway with your right hand, pressing the wallpaper against the wall to the right. Place the razor knife against the top corner of the doorway where the door frame meets the wall with your left hand. Trim the wallpaper by simultaneously sliding both the guide and the razor knife down to the bottom of the doorway.

Press the trim guide at the top right corner of the doorway, pressing the wallpaper up and against the wall between the doorway and the ceiling. Place the razor knife against the top corner where the door frame meets the wall and trim the excess wallpaper by simultaneously sliding both the guide and the razor knife to the left, stopping at the left corner

Place the trim guide against the wallpaper at the top left corner and press the wallpaper against the wall to the left. Position the razor knife at the top left corner against the door frame and trim the wallpaper by simultaneously sliding the knife and the guide down to the floor.