Print size reference
Photo print sizes: exact dimensions
The label on a paper pack is not always its exact physical size. Use the dimensions below as a reference, then match your printer driver and packaging before a tight layout.
Short answer: 4 x 6 inches is exactly 101.6 x 152.4 mm. An exact 10 x 15 cm cut is 100 x 150 mm. Retailers and printer drivers sometimes use “10 x 15 cm” as a rounded name for 4 x 6 inch media, so the two labels are not reliable substitutes when millimeters matter.
10 x 15 cm vs 4 x 6 in
Both formats have a 2:3 aspect ratio, so they frame the same shape without cropping. Their physical dimensions differ by 1.6 mm in width and 2.4 mm in height. That small difference can decide whether another print fits on a sheet or whether a printer reports a paper mismatch.
| Label | Exact dimensions | Aspect ratio | Use in PrintsOptimizer |
|---|---|---|---|
| 4 x 6 in | 101.6 x 152.4 mm 10.16 x 15.24 cm | 2:3 | Choose the rounded 10 x 15 cm / 4 x 6 in preset. |
| Exact 10 x 15 cm | 100 x 150 mm 3.937 x 5.906 in | 2:3 | Choose the exact metric preset. |
| Manufacturer variant | For example, 101 x 152 mm | Approximately 2:3 | Choose Custom and enter the package dimensions. |
The safest rule is simple: use the dimensions printed on the pack or shown in the printer driver, not the rounded product name.
Common photo print dimensions
| Print name | Millimeters | Centimeters | Inches | Shape |
|---|---|---|---|---|
| Exact 9 x 13 cm | 90 x 130 | 9 x 13 | 3.543 x 5.118 | About 1.44:1 |
| Exact 10 x 15 cm | 100 x 150 | 10 x 15 | 3.937 x 5.906 | 2:3 |
| 4 x 6 in | 101.6 x 152.4 | 10.16 x 15.24 | 4 x 6 | 2:3 |
| 5 x 7 in | 127 x 177.8 | 12.7 x 17.78 | 5 x 7 | 5:7 |
| Exact 13 x 18 cm | 130 x 180 | 13 x 18 | 5.118 x 7.087 | About 13:18 |
| Exact 15 x 20 cm | 150 x 200 | 15 x 20 | 5.906 x 7.874 | 3:4 |
| 8 x 10 in | 203.2 x 254 | 20.32 x 25.4 | 8 x 10 | 4:5 |
| Exact 20 x 30 cm | 200 x 300 | 20 x 30 | 7.874 x 11.811 | 2:3 |
Common sheet sizes for photo layouts
The sheet is the physical paper that holds one or more prints. ISO sizes have standardized trimmed dimensions; inch-named sheets use exact inch conversion. A3+ is a common professional photo-paper convention rather than an ISO size.
| Paper | Millimeters | Inches | Notes |
|---|---|---|---|
| A6 | 105 x 148 | 4.134 x 5.827 | ISO 216 |
| A5 | 148 x 210 | 5.827 x 8.268 | ISO 216 |
| A4 | 210 x 297 | 8.268 x 11.693 | ISO 216 |
| A3 | 297 x 420 | 11.693 x 16.535 | ISO 216 |
| A3+ | 329 x 483 | 12.953 x 19.016 | Professional photo-paper convention |
| US Letter | 215.9 x 279.4 | 8.5 x 11 | North American office paper |
| 13 x 19 in | 330.2 x 482.6 | 13 x 19 | Close to, but not identical to, A3+ |
Aspect ratio determines cropping
A 2:3 camera image fits a 4 x 6 inch or exact 10 x 15 cm cell without changing shape. It does not exactly match a 5 x 7 inch or 8 x 10 inch cell. To fill those cells, crop the long edge; to preserve the whole image, accept blank space.
PrintsOptimizer places rectangles at the dimensions you request. It does not crop image pixels. Decide the finished print size in your editor or Lightroom Classic, then use that size in the optimizer.
How to choose the correct preset
- Read the package dimensions. Prefer millimeters when the pack provides them.
- Match the printer driver. Some drivers group 4 x 6 in under a rounded 10 x 15 cm label.
- Use Custom for variants. Enter 101 x 152 mm, perforated stock, or another manufacturer-specific cut exactly.
- Add real margins and gutters. A nominal fit may fail once the printable margin or cutting gap is included.
- Print one test sheet. Measure it before committing expensive paper or a full batch.
Ready to test a paper and print combination? Enter the physical dimensions and let the optimizer try rotated and mixed layouts.
Open the optimizer