A 13×18 print slips perfectly into a 13×18 cm frame — but only if you skip the mat. Add one, and the frame has to grow by twice the mat’s border on each side. That single detail trips up more buyers than any other, and it’s the difference between a print that drops in cleanly and one that gets trimmed at the edges. The table below shows the exact frame size you need for the most common mat widths.
What Size Frame Fits A 13×18 Picture Without A Mat?
Without a mat, the frame size matches the picture size exactly: 13×18 cm. Frame makers label frames by the print or glass they hold, not the outer molding, so a frame sold as 13×18 cm holds a 13×18 cm image with no trimming or gap.
If you’re shopping in the US, look for a 5×7 frame; the fit is identical.
The most common mistake is confusing the photo size with the outer frame size. A frame labeled 5×7 or 13×18 refers to the opening, not the full width of the frame on the wall, so the finished piece will hang larger than the listed size once you account for the border.
How Much Bigger Does The Frame Get With A Mat?
A mat adds to each side, so the frame must be larger than 13×18 cm by double the mat border on every edge. For a 3 cm mat border around a 13×18 cm image, one sizing guide gives a 19 x 24 cm frame.
The math is simple: mat border × 2 added to each dimension of the picture. A 3 cm mat means 6 cm added to the width and 6 cm added to the height, giving 19 x 24 cm. Scale that rule for any mat width you choose.
| Mat Border | Frame Size Needed | Best For |
|---|---|---|
| No mat | 13×18 cm (5×7 in) | Tight, edge-to-edge display |
| 1 cm | 15 x 20 cm | Subtle breathing room |
| 2 cm | 17 x 22 cm | Everyday gallery look |
| 3 cm | 19 x 24 cm | Classic matted print |
| 4 cm | 21 x 26 cm | Fine-art framing |
| 5 cm | 23 x 28 cm | Large statement mat |
| 6 cm | 25 x 30 cm | Oversized mat, small image |
If you’d rather skip the math entirely, a tested roundup of 13×18 picture frames worth buying lists options that match these exact dimensions. FrameUSA’s guide to standard picture frame sizes confirms the US sizing convention behind these numbers.
Do Frame Sizes Include The Frame Border Or Just The Glass?
The listed frame size covers the print or glass area only — it does not include the outer molding or any matting. This is the single biggest source of returns: buyers assume “13×18” describes the whole piece hanging on the wall, then find the frame opening is smaller than expected when the molding is thick.
When you shop, check two numbers on the product page: the stated frame size (the opening) and any “overall dimensions” or “outer dimensions” line. A 13×18 cm frame with a wide molding can hang at 16 x 21 cm or more on the wall. Neither number is wrong — they measure different things.
For matted pieces, the opening gets smaller still. A frame sized 19 x 24 cm holds a 13×18 cm image behind a 3 cm mat, and the visible print area shrinks to just the image itself. If you want the mat visible around all four sides, the frame must clear the mat’s outer edge, which is why the sizing table above adds the full mat width twice.
FAQs
Is a 13×18 cm frame the same as a 5×7 inch frame?
Metric and imperial labels describe identical openings.
What if my picture is 13×18 inches, not centimeters?
Then you need a 13×18 inch frame, which is much larger — about 33×46 cm. Check the unit label carefully. Mixing up cm and inches is the fastest way to order a frame that arrives far too small.
Can I use a larger frame without a mat?
Yes, but the print will shift and look undersized inside the opening. You’d need mounting tape or a custom mat to hold it centered. For a clean look with no mat, match the frame size to the picture exactly.
References & Sources
- FrameUSA. “Standard Picture Frame Sizes.” Supports US sizing conventions and the 5×7 inch equivalent.
- HALBE Rahmen. “Picture Frame Sizes & Formats.” Supports mat sizing math and the 19 x 24 cm frame for a 3 cm mat border.
- Modulor. “Picture Frames by Size: 13×18 cm.” Confirms 13×18 cm as a standard frame size.
