How to Measure Artwork for Custom Picture Framing

Precise measurements are the foundation of every great frame job.

An accurate measurement is the single most important step in picture framing. A sixteenth-of-an-inch error can mean a mat that overlaps your image or a frame that gaps at the corners. This guide covers the tools, techniques, and pitfalls for measuring prints, photographs, stretched canvas, and oversized artwork so your order arrives ready to assemble.

Step-by-Step: Measuring Artwork for a Custom Frame

Start with a rigid steel ruler or a quality aluminum T-square rather than a cloth tape measure, which stretches and sags. For pieces larger than 24 inches, use a 48-inch straightedge or a retractable steel tape locked at the measurement point. A mechanical pencil with 0.5 mm lead lets you mark reference points without smudging. Keep a notepad dedicated to framing measurements so numbers do not get lost. If you are measuring the glazing already in an old frame, lay the piece flat on a clean surface and measure the glazing itself, not the frame opening, since the glazing rests inside the rabbet and is slightly smaller than the visible opening.

Measuring Flat Prints and Photographs

Place the print face-up on a flat, clean surface. Measure the image area, not the paper. Most photographic prints include a small white border around the image; your mat window will cover this border, so the critical number is the visible image width and height. Measure at three points along each axis: top, middle, and bottom for width; left, center, and right for height. If the numbers differ, use the smallest measurement to ensure the mat window does not reveal unprinted paper. Record measurements in inches to the nearest 1/8 inch.

Measuring Stretched Canvas

Stretched canvas is measured differently from flat paper. Measure the front face of the canvas from outer staple edge to outer staple edge, which gives you the finished face dimension. Do not wrap the tape around the stretcher bar depth. Standard stretcher bars add 3/4 inch or 1-1/2 inches of depth on each side; this depth determines the correct frame profile, standard or deep. Record three measurements: face width, face height, and stretcher bar depth. If the canvas is gallery-wrapped with the image continuing around the sides, note this as well, since it affects whether you need a floater frame or a traditional frame with a visible lip.

Measuring Oversized and Irregular Artwork

For pieces larger than 32 x 40 inches, lay the artwork flat and secure the corners with soft weights to prevent curling. Use a long straightedge rather than a flexible tape. Measure in inches and round to the nearest 1/8 inch, never round up to the next whole number. Irregular shapes such as oval mats or non-rectangular art require a template: trace the outline on kraft paper, then measure the maximum width and height of the traced shape. For three-dimensional items destined for shadow boxes, measure the width, height, and depth of the object, adding at least 1/4 inch of clearance on each side so the item does not press against the glazing.

Common Measurement Mistakes

The most frequent error is confusing image size with paper size. A print labeled 11x14 often has an image area of roughly 10.5 x 13.5 with white borders. Ordering a mat with an 11x14 window for this print will reveal unprinted paper on every side. Another common mistake is measuring in the wrong orientation: always record width before height. Swapping these numbers turns a portrait frame into a landscape frame. Finally, avoid measuring artwork that is still rolled or curled. Let it flatten under weight for at least 24 hours before measuring, since a curled piece will give shorter readings than its true dimensions.

Recording and Submitting Your Measurements

Write every measurement in the format Width x Height in inches, and label each number clearly: image size, paper size, and if applicable, stretcher depth. When ordering from CustomPictureFrames.com, enter the artwork dimensions in the fields provided and the system calculates the frame and mat sizes automatically. Double-check that your width and height are not transposed before adding to cart. If your artwork falls between standard sizes, our precision-cut mats and frames are built to the exact dimension you specify, down to 1/8 of an inch.

Frequently Asked Questions

Should I measure the image or the paper when ordering a frame?

Measure the image area you want visible through the mat window. The mat will overlap the image by approximately 1/8 inch on each side to hold it in place, so the actual window cut is slightly smaller than your image dimensions. If you are framing without a mat, measure the full paper size instead.

How much tolerance should I allow in my measurements?

Aim for accuracy within 1/8 inch. Our frames and mats are precision-cut to match the dimensions you provide. Adding extra tolerance can result in the artwork shifting inside the frame. Measure twice at different points and use the smaller number if there is any discrepancy.

Can I measure artwork that is still in an old frame?

Yes, but remove it from the frame first if possible. If you must measure in-frame, measure the visible area through the existing mat window and note that the actual artwork extends beyond what is visible. The hidden portion is typically 1/8 to 1/4 inch per side under the mat overlap.