Picture Frame Calculator
Work out frame moulding length, glass size and mat opening for any artwork.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
The frame dimensions use the artwork, mat border, and moulding width. Moulding length includes a 10% cutting allowance; cost uses a separate 15% allowance. Confirm mitre cuts and supplier lengths before purchasing.
Worked example
calculated with the default values below
Artwork width 16 in · Artwork height 12 in · Mat border width 2 in · Mat overlap onto the artwork 0.25 in · Frame moulding width 1 in · Moulding price per foot 3 $ Frame outer width 22.00 in · Frame outer height 18.00 in · Moulding needed 88.0 in · Moulding needed 7.33 ft · Glass width 20.00 in · Glass height 16.00 in · Mat opening 15.5 x 11.5 in · Moulding cost 23.00 $
General background references
Disclaimer
These calculators provide planning estimates only. Building codes, wiring regulations and safety requirements differ by country and change over time, and nothing here replaces a licensed professional or a permit. For structural, electrical or gas work, follow local code and have the installation inspected.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
Pm = 2 × (W + H + 4b + 4f); L(in) = Pm × 1.10; L(ft) = Pm ÷ 12 × 1.10; C = Pm ÷ 12 × p × 1.15
- Pm
- Outer perimeter (in)
- W
- Artwork width
- H
- Artwork height
- b
- Mat border width
- f
- Frame moulding width
- C
- Moulding cost
Glass dimensions = artwork dimensions + 2 × mat border; frame outer dimensions = glass dimensions + 2 × frame width. Mat opening = artwork dimensions − 2 × overlap and must remain positive. Moulding includes a 10% cutting allowance; cost includes a separate 15% allowance.
Frequently asked questions
What if the mat overlap is wider than the artwork?
The calculator rejects the dimensions if subtracting twice the overlap would make the mat opening zero or negative. Reduce the overlap or enter larger artwork dimensions.
Does the moulding length include cutting waste?
Yes. Moulding length is the outer frame perimeter plus a 10% cutting allowance. For a 22 × 18 inch outer frame, the perimeter is 80 inches and the estimated purchase length is 88 inches (7.33 feet). Cost uses a separate 15% allowance; confirm cuts and stock lengths with your supplier.