Picture Frame Calculator

This calculator relies on standard geometry and woodworking formulas to account for the artwork dimensions, mat board borders, moulding profile width, and the rabbet overlap. The total required moulding length is calculated using the formula: Required Moulding = (Frame Width × 2) + (Frame Height × 2) + (Mat Width × 4) + (Mat Height × 4) + (Moulding Width × 8) - (Rabbet × 4) + (Fudge Factor × 4). This accounts for 45-degree miter cuts at each corner and includes a small waste allowance. Glazing and inner dimensions are similarly derived by adding or subtracting the rabbet depth and moulding width to ensure the glass and backing fit securely within the frame groove.

Imagine you want to frame a photograph that is 10 inches wide by 8 inches high. You select a moulding width of 1.5 inches, a rabbet depth of 0.25 inches, a mat border of 2 inches on all sides, and include a 1-inch fudge factor for safety cuts. First, compute the outer frame width and height by adding the artwork dimensions, double the mat width, double the moulding width, and subtracting double the rabbet depth. For the width: 10 + (2 × 2) + (2 × 1.5) - (2 × 0.25) = 16.5 inches. For the height: 8 + (2 × 2) + (2 × 1.5) - (2 × 0.25) = 14.5 inches. Applying the complete moulding equation yields approximately 76 inches of linear moulding material required to successfully construct your custom picture frame.

Always double-measure your artwork before inputting dimensions to avoid cutting materials too short. Remember to factor in a 'rabbet allowance' so your glass, mat, and backing board slide smoothly into the frame back without jamming. Finally, always purchase 10% to 15% extra moulding beyond the calculated baseline to account for potential miscuts during the miter-sawing process.