Guides · Printing and framing
Metric and inch frame sizes: which ones match?
Metric and inch frames rarely match exactly. 30 × 40 cm has the 12 × 16 in shape but is 4.8 mm narrower; 40 × 50 cm shares the 8 × 10 shape and 50 × 70 cm the 5 × 7 shape; A sizes match none. Print a file of the right shape at the frame's exact size.
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Which metric frames match an inch size?
A frame fits a print when both have the same shape and the print is no more than a millimetre or two bigger. Here is every metric frame size the tools know, its size in inches, and the nearest inch print of the same shape:
| Metric frame | In inches | Shape | Same-shape inch print | Pixels at 300 DPI |
|---|---|---|---|---|
| 10×15 cm | 3.9 × 5.9 in | 2:3 | 4 × 6 in (print 1.6 × 2.4 mm bigger) | 1,181 × 1,772 |
| 13×18 cm | 5.1 × 7.1 in | 13:18 | None | 1,535 × 2,126 |
| A5 | 5.8 × 8.3 in | 1:√2 | None | 1,748 × 2,480 |
| 20×30 cm | 7.9 × 11.8 in | 2:3 | 8 × 12 in (print 3.2 × 4.8 mm bigger) | 2,362 × 3,543 |
| A4 | 8.3 × 11.7 in | 1:√2 | None | 2,480 × 3,508 |
| 30×40 cm | 11.8 × 15.7 in | 3:4 | 12 × 16 in (print 4.8 × 6.4 mm bigger) | 3,543 × 4,724 |
| A3 | 11.7 × 16.5 in | 1:√2 | None | 3,508 × 4,961 |
| 40×50 cm | 15.7 × 19.7 in | 4:5 | 16 × 20 in (print 6.4 × 8 mm bigger) | 4,724 × 5,906 |
| 50×70 cm | 19.7 × 27.6 in | 5:7 | Shape of 5×7 only | 5,906 × 8,268 |
Which metric frame fits a US print?
The other way round: a print in inches, and the common metric frame closest to it.
| Inch print | In cm | Closest metric frame | Print vs frame |
|---|---|---|---|
| 4×6 | 10.2 × 15.2 cm | 10 × 15 cm (same shape) | 1.6 × 2.4 mm bigger |
| 5×7 | 12.7 × 17.8 cm | 13 × 18 cm | 3 × 2.2 mm smaller, different shape |
| 8×10 | 20.3 × 25.4 cm | 20 × 25 cm (same shape) | 3.2 × 4 mm bigger |
| 11×14 | 27.9 × 35.6 cm | 28 × 35 cm | 0.6 mm narrower, 5.6 mm longer, different shape |
| 12×16 | 30.5 × 40.6 cm | 30 × 40 cm (same shape) | 4.8 × 6.4 mm bigger |
| 12×18 | 30.5 × 45.7 cm | 30 × 45 cm (same shape) | 4.8 × 7.2 mm bigger |
| 16×20 | 40.6 × 50.8 cm | 40 × 50 cm (same shape) | 6.4 × 8 mm bigger |
| 18×24 | 45.7 × 61 cm | 45 × 60 cm (same shape) | 7.2 × 9.6 mm bigger |
| 20×30 | 50.8 × 76.2 cm | 50 × 75 cm (same shape) | 8 × 12 mm bigger |
| 24×36 | 61 × 91.4 cm | 60 × 90 cm (same shape) | 9.6 × 14.4 mm bigger |
What if the print is a few millimetres too big?
A millimetre or two disappears under the frame's lip. More than that, and the print buckles or won't go in. You can trim it with a craft knife and a ruler, use a mat (passe-partout) cut for the print, or, best, print it at the frame's exact size: a file of the same shape prints at 30 × 40 cm just as well as at 12 × 16 in, and a print shop can make either.
Why don't A4 and A3 match any US frame?
A sizes have their own shape, 1:√2, chosen so that halving a sheet gives the next size down with the same proportions. No inch frame shares it, so an A4 print in an 8.5 × 11 frame is too tall, and in an 8 × 10 it is cropped. Use A-size frames for A-size prints, or a mat cut for them. More on the two papers: A4 vs US Letter.
How to choose
- Read the frame's exact size off its label (cm or inches).
- Find its shape in the tables above, or on the print size chart.
- Use a file of that shape: for a printable pack, the ratio file; for a photo, crop it to that frame in Photo to Frame.
- Print at the frame's exact size, not the nearest size in the other system.
Frequently asked questions
Will a 12x16 print fit a 30x40 cm frame?
Not quite: 12 × 16 in is 30.5 × 40.6 cm, 4.8 × 6.4 mm bigger than the frame. The shapes match, so print the 3:4 file at 30 × 40 cm instead, or trim the edges.
Is 40x50 cm the same as 16x20?
Same 4:5 shape, not the same size: 16 × 20 in is 40.6 × 50.8 cm. An 8x10 or 16x20 file prints at 40 × 50 cm without cropping.
What is the metric equivalent of 8x10?
20 × 25 cm has the same 4:5 shape and is 3.2 × 4 mm smaller. 8 × 10 in itself is 20.3 × 25.4 cm.
Does any inch frame fit an A4 print?
No standard inch frame has A4's 1:√2 shape. An A4 print (8.3 × 11.7 in) is 17.6 mm too tall for an 8.5 × 11 frame; use an A4 frame or a larger frame with a mat cut for A4.
Which file should I print for a 50 x 70 cm frame?
A 5:7 file, if it has the pixels (5,906 × 8,268 at 300 DPI). Otherwise the A-series file: filling 50 × 70 cm trims about 1% off its top and bottom, and an A1 file still gives about 356 DPI there.
Sources and how the numbers were worked out
Pixel, crop and size figures on this page are calculated from the same size data the FrameReady tools use (inches or millimetres × DPI), not copied from elsewhere.
- FrameReady print size chart (inches, cm and mm for every size)
- FrameReady centimetre frame pages (e.g. 30x40 cm)