Picture Frame Sizes: Opening vs Outside Dimensions
A picture frame’s nominal size usually refers to the photo, glass or matboard it can hold. It is not the frame’s outside measurement. The front sight opening, back rabbet recess and finished outside edges are three different boundaries.
To buy a frame, use the seller’s component-size convention. To reserve space on a wall, use the finished outside dimensions. To cut custom rails, specify which measuring edge your saw uses.
Worked example
- Artwork11" × 14"
- Package / glass (dashed)11" × 14"
- Actual rabbet recess11 1/8" × 14 1/8"
- Visible sight opening10 5/8" × 13 5/8"
- Finished outside13 5/8" × 16 5/8"
Inputs
- Artwork: 11" × 14".
- Face width 1 1/2"; rabbet overlap 1/4"; clearance 1/16" on each side.
Calculated result
- Board / glass / backing
- 11" × 14"
- Actual rabbet recess
- 11 1/8" × 14 1/8"
- Visible sight opening
- 10 5/8" × 13 5/8"
- Finished outside
- 13 5/8" × 16 5/8"
An 11 × 14 photo in this no-mat example needs an 11 × 14 package. The larger calculated outside rectangle is the space the finished frame occupies, not the size to select in a store’s opening-size menu.
Continue this example in StudioCalculated with the same FramePlan engine as the tool. Inches display to the nearest 1/16; internal dimensions use 0.01 mm precision. Examples are plans, not measurements of a purchased frame.
Which dimension are you measuring?
- Artwork size
- The physical photo, print or artwork area used by the calculation. Decide which edges can be covered; do not mix image size with a larger sheet of paper.
- Mat window
- The opening cut through the matboard. For an overlapped rectangular image, each dimension is artwork size minus twice the overlap.
- Board / glass / backing size
- The outer size of the rectangular package placed in the frame. Mat borders grow this size; window overlap does not.
- Nominal frame size and actual rabbet
- A shop’s label usually describes the components it accommodates, not the outside. The actual back recess may include additional fitting room. Check the maker’s sizing convention and measure it before ordering parts.
- Sight opening
- The opening visible from the front of the frame. The rabbet lip covers the package edges, so this is smaller than the actual rabbet recess.
- Finished outside size
- The frame measured between its outermost edges. Use it for wall space and long-point rail lengths; do not use it as a retail opening size.
Why the same nominal opening has different outside sizes
Two frames can accept the same glass but have different face widths. The wider profile extends farther beyond the visible opening. A wider rabbet lip, meanwhile, covers more of the package from the front. Neither is the rabbet depth, which controls how thick a stack fits.
FramingLab calculates each axis in this order: package → add clearance on both sides → subtract lip overlap on both sides for the sight opening → add face width on both sides for the outside size. Its fitting-clearance field is per side. The default 1/16 inch per side adds 1/8 inch to the whole recess, not 1/16 inch overall.
A manufacturer’s actual recess can exceed its nominal size. Frame Destination’s profile 501 sizing specification identifies component size separately from the extra fitting room it builds into its frames. That is a maker-specific convention, not a guarantee about every ready-made frame.
Measure the boundary you actually need
- Confirm the physical photo or matboard package dimensions. If you add a mat, its outside board size becomes the package size.
- For an existing frame, measure its back recess and check its usable depth; do not infer them from the front opening.
- For a new frame design, measure the moulding face and lip widths and choose fitting clearance.
- Read the finished outside result for wall placement. Check glass, matboard and backing against the recess before assembly.
Common mistakes
- Ordering a retail frame using the calculator’s finished outside result.
- Calling the front sight opening the glass size: the lip hides the glass edges.
- Adding twice the full face width to the artwork while ignoring both lip overlap and clearance.
- Using this no-mat example for a matted print without first recalculating the board.
Use the corresponding tool
Calculate finished outside frame dimensions
For a mat around the photo, calculate the artwork, mat and frame together. If you already own a frame, work out its mat window and borders before ordering components.
These are rectangular framing dimensions. Floater frames, shadowbox interiors and conservation mounting decisions require their own specifications; a dimensional plan does not certify those constructions.