How to use the picture frame stock calculator
- Enter the width and height of the art, glass or panel that will sit in the rabbet.
- Enter the width of the molding across the face, from the outside edge to the inside edge of the rabbet.
- Set the play on each side so the art drops in. The 1/16 inch shown is an example.
- Open More options to enter the stick length and the saw cut, then read the cut lengths and the sticks to buy.
Formula
opening width = art width + 2 x play
opening height = art height + 2 x play
top and bottom pieces = opening width + 2 x molding width
side pieces = opening height + 2 x molding width
total molding = 2 x (top piece + side piece)
All lengths are to the long point of a 45 degree miter. The pieces are packed into sticks longest first with a saw cut between them.
A 16 by 20 inch print
With 1.75 inch molding and 1/16 inch of play, the opening is 16.125 by 20.125 inches. The top and bottom pieces are 19.625 inches and the sides 23.625 inches, which is 86.5 inches of molding in all, or 7.21 feet. They fit in one 96 inch stick with room for the cuts.
A 24 by 36 inch print in 2.5 inch molding has sides of 29.125 and 41.125 inches, 140.5 inches in total, and needs 2 sticks of 96 inches. An 8 by 10 inch print in 1 inch molding needs 44.5 inches, which fits in one stick of 48 inches.
Measuring the molding width
Measure the molding from its outer edge to the inside edge of the rabbet, the notch that holds the art. That distance is what the frame adds on each side of the opening. Do not measure only the visible face, because part of it is hidden behind the lip.
Moldings that are very wide or have a deep profile can lose a little at the miter, so cut one piece first and test the corner.
Cutting and joining
Cut the pieces with a miter saw set to 45 degrees, and cut the opposite sides one after another from the same setting so they come out the same length. Glue the corners, clamp them square and add pins or a spline if the molding is wide. A little extra on each piece lets you trim for a perfect fit.
Related framing tools
Size the mat with the Frame Mat Size Calculator, set angles with the Miter Angle Calculator, add measurements with the Tape Measure Calculator, and place finished frames with the Picture Hanging Calculator.
Assumptions and limits
- The frame is a rectangle with four 45 degree mitered corners.
- Play is the same on every side.
- The saw cut is lost between pieces on one stick, not at the ends of the stick.
- Glass, backing, mat thickness and hardware are not modeled.
Frequently asked questions
How much molding do I need for a picture frame?
Add the opening and twice the molding width for each pair of sides, then double. A 16 by 20 inch print in 1.75 inch molding needs 86.5 inches, or 7.21 feet.
Do I measure to the long point or the short point?
The long point, the outside corner of the miter. That is the length of the piece at its longest edge. The inside edge is shorter by twice the molding width.
How much play should I leave around the art?
A small gap of about 1/16 inch lets the art drop in. The page uses that as an example, and you can enter any value.
How many sticks of molding should I buy?
The page packs the four pieces into sticks of the length you enter. Larger frames, like a 24 by 36 inch print, may need two sticks.