Picture Frame Calculator

Picture Frame Calculator. Enter your artwork dimensions, mat width, and frame border width to calculate the perfect picture frame size. You'll get the outer frame dimensions, mat opening size, and frame perimeter — everything you need to order or build a custom frame. Also try the Appliance Wattage Calculator.

Results

Outer Frame Width

Outer Frame Height

Mat Opening Width

Mat Opening Height

Inner Frame (Glass) Width

Inner Frame (Glass) Height

Frame Perimeter

How do I measure a picture frame?

Picture frames are measured by their inner opening — the space that holds the artwork or glass — not the outer edge. Measure the width and height of your artwork first, then add the mat width and frame border width on each side to determine the full outer frame dimensions. See also our find Energy Use Intensity (EUI) with EUI Calculator (Energy Use Intensity).

What is a mat and why does it matter for frame sizing?

A mat (or mount) is a decorative border placed between the artwork and the frame. It provides visual breathing room for the piece and protects the artwork from touching the glass. The mat width adds to the overall inner frame size, so you need to account for it when ordering a frame.

What is the difference between inner and outer frame dimensions?

The inner frame dimension (also called the rabbet or sight size) is the opening that holds your artwork and glass. The outer frame dimension is the total visible size of the frame including the moulding border. Both measurements are important — inner for glass/mat cutting, outer for hanging and wall space planning.

What is a standard picture frame size?

Common standard frame sizes in inches include 4×6, 5×7, 8×10, 11×14, 16×20, and 24×36. In centimeters, popular sizes are 10×15, 13×18, 20×25, 28×35, and 40×50. Using a standard size is cheaper since pre-cut glass and mats are readily available.

How much mat width should I use?

A mat width of 2–3 inches (5–8 cm) works well for most standard prints and photos. Larger artwork benefits from wider mats (3–4 inches). A 'weighted' mat — slightly wider at the bottom — is a popular technique that makes the artwork appear optically centered.

How do I calculate the frame perimeter for buying moulding?

The frame perimeter is calculated as (outer frame width + outer frame height) × 2. This tells you the total length of moulding needed. Always add 10–15% extra to account for mitered corners and cutting waste.

Can I use this calculator for custom frame sizes?

Yes. Simply enter your exact artwork dimensions, your desired mat width, and the width of the frame moulding. The calculator will output all the custom dimensions you need — inner opening, outer size, and perimeter — whether you are ordering from a framer or building the frame yourself.

Does the mat opening size match my artwork size?

The mat opening is typically cut slightly smaller than the artwork — usually about 0.25 inches (0.5 cm) smaller on each side — so the mat overlaps the artwork edges and holds it in place. This calculator shows the artwork dimensions as the mat opening reference; apply a small overlap reduction when ordering a cut mat. You might also find our Dilution Ratio Calculator useful.