Yes. Mat borders are designed with a 3mm overlap on each edge to hold your artwork securely in place. This overlap is intentional and helps ensure your artwork is mounted cleanly and safely.
If you’re experienced and don’t want any overlap, you can add 6mm to each artwork dimension when entering your size. However, we generally don’t recommend doing this unless you’re confident with precise measuring and mounting, as the overlap is there to make framing easier and more forgiving.
All frames also include a 5mm rebate, which is the standard inner lip of a picture frame that holds the artwork, mat, and glass in place. This means a small portion of the artwork edges will sit behind the frame once assembled. This is a normal feature of all picture frames, not something unique to Framefox.