Calculate picture frame dimensions, mat opening size, glass area, and framing costs. Plan custom framing for photos, art, and prints with exact measurements.
The Picture Frame Calculator helps you determine the exact dimensions for custom framing projects, including frame size, mat opening, mat border widths, glass area, and overall wall space needed. Custom framing can be expensive, and getting measurements wrong wastes both materials and money.
This tool calculates everything from the inside mat opening (with proper overlap to hold your artwork) to the outer frame dimensions based on your chosen molding width. It accounts for standard framing practices like 1/8" art overlap on each side, proper mat border proportions (wider on the bottom for visual balance), and backing board dimensions.
Whether you're framing family photos, fine art prints, diplomas, or creating a gallery wall, this calculator ensures your measurements are precise before you cut a single piece of mat board. It also estimates material costs and compares common mat configurations. That helps you translate the visible art size into the actual opening, outer frame, and wall-clearance dimensions the project really needs.
Custom framing combines several measurements that all depend on each other: art size, overlap, mat borders, glazing, and molding width. A mistake in one number usually ruins a sheet of mat board or a piece of frame stock.
This calculator is useful because it keeps those linked dimensions in one place and makes the finished frame size clear before you buy materials or start cutting.
Mat Opening = Art Size - (2 × Overlap); Frame Size = Art Size + (2 × Mat Border) + (2 × Lip); Outer Frame = Frame Size + (2 × Molding Width); Glass = Frame Size
Result: Mat opening: 7.75×9.75", Frame: 13.25×15.25", Outer: 16.25×18.25"
An 8×10 photo with 2.5" mat borders needs a 13.25×15.25" frame with a mat opening of 7.75×9.75" (with 1/8" overlap on each side).
Professional framing follows established proportional guidelines that balance the artwork with its surrounding mat and frame. The most common rule is the "inverse size relationship" — smaller artworks benefit from proportionally wider mat borders to give them presence, while large pieces can use narrower borders. A 4×6 photo typically looks best with 3" borders, while a 16×20 print might only need 2" borders.
Mat board comes in various grades and materials. Standard mats use wood pulp core and are fine for decorative framing. Conservation mats use acid-free materials that won't yellow or damage artwork over time. Museum-quality rag mats are 100% cotton fiber and recommended for valuable original artwork, photographs, and documents.
Custom framing at shops can cost $100-$500+ per piece. To save money, consider standard sizes that use pre-cut mats (8×10, 11×14, 16×20), frame multiple pieces at once for volume discounts, or do your own matting with a good mat cutter. The most expensive components are typically the frame molding and glazing — choosing simpler profiles and regular glass significantly reduces cost.
For most frames, 2-3 inches on the sides and top, and 2.5-3.5 inches on the bottom. The bottom border is traditionally wider (by 0.5") for visual balance — this is called "weighted bottom."
The mat overlaps the artwork by about 1/8" on each side to hold it in place. So the visible (window) opening is 1/4" smaller than the art in each dimension.
With a standard 2.5" mat border, you'd need approximately an 13×15" frame opening (or labeled as 13×15 at frame shops). Outer dimensions depend on molding width.
Regular glass is cheaper and scratch-resistant but heavy and breakable. Acrylic (Plexiglas) is lighter, shatter-resistant, and available with UV protection, but scratches more easily.
White and off-white mats are safest for most artwork. Colored mats should complement (not match) a color in the artwork. Dark mats can make artwork appear lighter and more dramatic.
Professional framers recommend at least 2 inches minimum. Narrower borders look cheap and don't provide enough visual breathing room for the artwork.