Picture Frame Mat Calculator
Picture Frame Mat Calculator
Enter the size of your frame or mat opening and the size of the artwork or photo you're framing. This calculates the width of the mat border on each side so your image sits perfectly centered.
The calculation is a simple even split — the leftover space between the frame and the image is divided by two and applied to each side — which gives the standard symmetric mat look used in most framing. Some professional framers intentionally use a very slightly larger bottom border, a technique called "visual centering" that compensates for an optical illusion where a perfectly symmetric mat can look bottom-heavy to the eye, but a mathematically even mat is the correct and most common default for anyone framing artwork themselves.
- Formula: Border Width = (Frame Dimension − Image Dimension) ÷ 2, applied separately to width and height.
- Even borders assume centering: this calculates a symmetric mat, which is the standard look — some framers use a slightly larger bottom border ("visual centering"), but symmetric is the mathematically even default.
- Works for custom mat cutting too: if you're cutting your own mat board, these numbers tell you exactly where to mark your cut lines from each edge.
What's a standard mat border width?
2–3 inches (5–7.5 cm) is common for most framed photos and art, though wider borders (3–4+ inches) are often used for a more gallery-style look.
What if my calculated borders come out negative?
That means your artwork is larger than the frame opening — you'll need a bigger frame or to trim/crop the artwork to fit.
Picture Frame Mat Calculator
Enter the size of your frame or mat opening and the size of the artwork or photo you're framing. This calculates the width of the mat border on each side so your image sits perfectly centered.
The calculation is a simple even split — the leftover space between the frame and the image is divided by two and applied to each side — which gives the standard symmetric mat look used in most framing. Some professional framers intentionally use a very slightly larger bottom border, a technique called "visual centering" that compensates for an optical illusion where a perfectly symmetric mat can look bottom-heavy to the eye, but a mathematically even mat is the correct and most common default for anyone framing artwork themselves.
- Formula: Border Width = (Frame Dimension − Image Dimension) ÷ 2, applied separately to width and height.
- Even borders assume centering: this calculates a symmetric mat, which is the standard look — some framers use a slightly larger bottom border ("visual centering"), but symmetric is the mathematically even default.
- Works for custom mat cutting too: if you're cutting your own mat board, these numbers tell you exactly where to mark your cut lines from each edge.
What's a standard mat border width?
2–3 inches (5–7.5 cm) is common for most framed photos and art, though wider borders (3–4+ inches) are often used for a more gallery-style look.
What if my calculated borders come out negative?
That means your artwork is larger than the frame opening — you'll need a bigger frame or to trim/crop the artwork to fit.