Quick answer: divide the pixel width and height by the print resolution. A 2400 × 3000 image maps to 8 × 10 inches at 300 pixels per inch, or 12 × 15 inches at 200 ppi. These are pixel-density calculations; they do not establish print quality.
Check your own photo: use the free photo-size checker to calculate print density, cropping, and the enlargement your print needs. Enter dimensions only; no photo upload.
Print sizes for common pixel dimensions
| Pixels | At 300 ppi | At 200 ppi |
|---|---|---|
| 1200 × 1800 | 4 × 6 in | 6 × 9 in |
| 1500 × 2100 | 5 × 7 in | 7.5 × 10.5 in |
| 2400 × 3000 | 8 × 10 in | 12 × 15 in |
| 3300 × 4200 | 11 × 14 in | 16.5 × 21 in |
| 3550 × 4730 (about 17 MP) | about 11.8 × 15.8 in | about 17.7 × 23.6 in |
The last row illustrates the approximate output limit. On iOS 1.1.10, very large photos may be processed at a smaller size on devices with less memory; check the actual finished dimensions. A file can contain enough pixels for a print size while still looking soft or showing artifacts. Inspect the result and order a small test print first.
Working backwards from the print you want
Want a 5 × 7 at 300 ppi? You need about 1500 × 2100 pixels. With a 4× upscale, the source only has to be about 375 × 525. That is why upscaling works well for old small downloads, scans made at low resolution, and crops.
When a big print will still look soft
- The source was blurry. Upscaling enlarges blur along with everything else.
- The source was very small, such as a 100-pixel thumbnail. The model has too little to work with.
- Heavy JPEG compression. Blocky artifacts can turn into strange textures at print size. Try Denoise first.
Order a small test print before a large one, and view the result at 100% on screen first. Printers usually accept the saved file from Photos directly.