How to Measure a Picture Frame: A Complete Guide

Ever bought a picture frame online only to find your cherished photo swims in a sea of empty space, or worse, refuses to fit at all? It’s a common frustration, and one that can easily be avoided with a little bit of know-how. Correctly measuring a picture frame, or the space it’s meant to hold, is essential for ensuring your artwork is displayed beautifully and securely. Whether you’re replacing a broken frame, commissioning custom artwork, or simply wanting to swap out photos in an existing frame, accurate measurements are the key to success. A properly sized frame enhances the impact of your piece, prevents damage, and saves you the hassle of returns and resizing.

But understanding the different measurements – inner dimensions, outer dimensions, rabbet depth – can feel a little confusing. Each plays a critical role in the final outcome. Taking the time to understand how these measurements work will ensure your pictures are perfectly housed with a professional look. Getting these details right can be the difference between a stunning display and a frustrating headache.

What size picture frame do I really need?

How do I measure a picture frame for the size of the picture it holds?

To determine the picture size a frame will hold, measure the inside dimensions of the frame, specifically the width and height of the opening at the back where the picture will sit. This provides the visible area, which dictates the correct picture size.

It’s crucial to measure from the inside lip, or “rabbet,” on the back of the frame, not the outside dimensions. The rabbet is the recessed area that holds the picture, glass, and backing. Use a ruler or measuring tape to get accurate measurements of both the width and the height of this inner space. Be as precise as possible, measuring to the nearest millimeter or 1/16th of an inch, as even small discrepancies can lead to your picture not fitting correctly.

Keep in mind that some of the picture will be covered by the frame’s lip. This is known as the “overlap” or “rabbet overlap.” Typically, this overlap is about 1/4 inch (6mm) on each side. This overlap ensures the artwork stays securely in place. The inside dimensions you measure represent the *visible* portion of your artwork once framed. Therefore, when printing or selecting artwork, make sure the key elements you want to be visible are within the measured dimensions.

What’s the difference between measuring the inside and outside of a frame?

The inside measurement of a frame determines the maximum size of artwork or photo it can hold, while the outside measurement indicates the overall dimensions of the frame itself and how much wall space it will occupy.

Think of it this way: the inside measurement is about what *fits in* the frame, focusing on the visible artwork. You need to know these dimensions to ensure your picture isn’t too big and will be properly displayed. Typically, you’ll measure the height and width of the opening on the back of the frame, where the artwork will sit. Minor discrepancies (e.g., 1/8 inch) are usually acceptable, as the frame’s lip will overlap the edges of the artwork slightly, holding it in place. Some frames come with rebates, little steps inside the frame that hold everything in place. These will affect your inside measurement.

The outside measurement, on the other hand, is about the frame’s physical size and is crucial for planning where to hang it or how it will look within a group of frames. This involves measuring the entire frame from edge to edge, including the molding. This measurement is important when considering wall space, framing clusters, or if you’re trying to match a frame’s external appearance with existing decor. Remember that a wider frame molding will naturally increase the overall outside dimensions.

How do I account for the frame’s rabbet when measuring for glass or artwork?

The rabbet is the recessed area on the inside edge of the frame that holds the glass, artwork, and backing. When measuring for these components, you need to measure the rabbet’s dimensions directly, not the outer dimensions of the frame. This ensures your glass, artwork, and backing fit snugly inside without gaps or being too large.

To accurately measure the rabbet, use a ruler or measuring tape and measure the length and width from the inside edges of the rabbet. It’s crucial to measure from the “bottom” of the rabbet, where the glass and artwork will rest, rather than from the outer edge of the frame. Measure at several points along each side to account for any slight variations or imperfections in the frame. The smallest measurement obtained is typically the safest size to use for cutting your glass, mat, and artwork. Remember to measure precisely, and consider subtracting a tiny fraction of an inch (about 1/16") from both the length and width measurements to allow for slight tolerances and ease of insertion and removal. This small allowance prevents the glass or artwork from being too tight and potentially causing damage to the frame or the artwork itself. This is particularly important for delicate artwork that might be sensitive to pressure.

Where should I measure: along the front, back, or side of the frame?

You should measure along the *back* of the frame to determine the correct size for your picture or artwork. This is because the back of the frame represents the actual usable space inside where your artwork will sit.

Measuring along the front of the frame will give you the overall dimensions, which include the frame’s width and are not relevant for determining the size of the artwork it can hold. The side of the frame only provides its thickness or depth and is similarly unhelpful for determining artwork size. The rabbet, the inner lip that holds the artwork, is located on the *back* of the frame, and the dimensions between opposite rabbets are what dictate the proper artwork size. To ensure an accurate measurement, use a ruler or measuring tape and measure from the inside edge of the rabbet on one side to the inside edge of the rabbet on the opposite side. Repeat this for both the width and height to get the correct dimensions. This method will provide the precise size of artwork that will fit comfortably and securely within the frame.

What’s the best way to measure an oddly shaped (non-rectangular) frame?

The best way to measure an oddly shaped frame is to create a template of the opening. Use a large sheet of paper or cardboard, trace the inside edge of the frame, and then measure the key dimensions of the traced shape, such as its maximum width, maximum height, and any unique curves or angles.

To elaborate, tracing the inner opening gives you a precise representation of the size and shape needed for your artwork or matting. After tracing, you can measure straight lines (like the longest width and height) using a ruler or measuring tape. For curved sections, consider using a flexible measuring tape to follow the contour, or breaking the curve down into smaller, manageable segments. Note the measurements on your template, including where each measurement was taken to avoid confusion later. For unusually complex shapes, you might consider taking several key measurements at different points and drawing a grid over the template. This allows you to approximate the shape with a series of smaller rectangles or triangles. Alternatively, you can scan the template into a computer and use image editing software to accurately determine dimensions. The goal is to capture enough data points to confidently replicate or fit artwork into the frame opening.

How accurate do my measurements need to be when ordering frame components?

Accuracy is paramount. Aim for measurements that are accurate to within 1/16 of an inch (approximately 1.5mm) or even better. This precision ensures a snug and professional fit for your artwork within the frame. Anything less accurate can lead to gaps, bowing, or the inability to properly assemble the frame.

To elaborate, picture framing is all about close tolerances. While some very slight wiggle room is acceptable, larger inaccuracies will compound across the four sides of the frame. If your artwork is slightly smaller than the inner dimensions of the frame, it can shift around and potentially become damaged. Conversely, if the artwork is even slightly too large, it will be difficult to insert, potentially causing bending or damage to both the artwork and the frame components. It’s always better to err on the side of being slightly too small rather than too large. A small gap can often be addressed with shims or spacers behind the artwork. However, forcing an oversized piece into a frame can result in irreversible damage. Invest in a good quality measuring tape or ruler with clear and easy-to-read markings. Double-check your measurements multiple times and, if possible, have someone else verify them. This small investment in accuracy will save you time, money, and frustration in the long run.

Should I measure in inches, centimeters, or another unit for picture frames?

The best unit of measurement for picture frames is generally inches in the United States and centimeters or millimeters in most other countries. This is because frame manufacturers and retailers typically use these units, making it easier to find a frame that perfectly fits your artwork or photograph.

When measuring for a picture frame, precision is key. Whether you choose inches or centimeters, always measure the artwork or photograph itself, not the existing frame (if any). Measure the width and height of the image. These dimensions will dictate the “size” of the frame you need. For example, an 8x10 inch photograph requires an 8x10 inch frame opening. Remember to account for any matting you plan to use. If you’re using a mat, measure the outside dimensions of the mat, not the visible image size through the mat opening. While inches are common in the US, and centimeters elsewhere, consistency is what matters most. If you find a frame you love that’s measured in the “wrong” unit, online conversion tools can easily translate between inches and centimeters (1 inch = 2.54 centimeters). Double-checking your measurements and conversions will ensure that your picture fits perfectly within the frame.

And that’s all there is to it! Measuring for a picture frame might seem tricky at first, but hopefully, you’re feeling confident and ready to get started. Thanks for reading, and be sure to check back soon for more helpful tips and tricks to make your decorating dreams a reality!