Abstract: A depth and miter gauge is provided for easily and accurately marking lines on a piece of trim, such as J-channel trim, so that the trim can be appropriately cut to make a mitered joint. The depth and miter gauge generally includes a web having a first slot defining a first edge adjacent a first end of the web for making depth markings on the trim, and a first flange extending approximately perpendicularly from a first side of the web and having a mitered edge on each end thereof for making miter markings on the trim. The gauge may also include a second slot defining a second edge adjacent a second end of the web for making depth markings on the trim, and a second flange extending approximately perpendicularly from a second side of the web, in a direction opposite the first flange, and having a mitered edge on each end thereof for making miter markings on the trim.