Picture Frame Calculator
Enter your artwork or photo size and the mat border width to calculate the mat opening, overall frame size, and moulding needed.
What this calculator does
The Picture Frame Calculator turns your artwork or photo’s size into the practical numbers you need for framing: the mat opening to cut, the overall outer frame size, how much moulding to buy, and the glass or backing area required.
How the math works
The mat opening is slightly smaller than the artwork itself, since the mat typically overlaps the edges by about 1/8 inch on each side so nothing shows through the gap: Opening = Art Size – (2 × overlap). The overall frame size adds the mat border on every side: Frame Size = Art Size + (2 × border width). Moulding length is the frame’s perimeter, 2 × (width + height), with an extra 15% added to cover the mitered corner cuts and any mistakes.
Custom framers may use slightly different overlap and waste conventions, so treat the moulding estimate as a helpful starting point when ordering material, and always double-check your final mat opening against the actual artwork before cutting.