Image print sizes: pixels, aspect ratios and 300 PPI
Cropping a picture to an 8 × 10 proportion does not automatically give it enough pixels for an 8 × 10 inch print at 300 PPI. Check composition and resolution separately before delivering or ordering a print.
Calculate the pixels you need
Required pixels = print size in inches × target PPI. An 8 × 10 inch print at 300 PPI needs 8 × 300 = 2400 pixels across and 10 × 300 = 3000 pixels high. For centimetres, divide by 2.54 before multiplying by PPI.
PPI means image pixels per inch. DPI usually describes printer dots; people often call both “300 DPI”. Changing a resolution tag cannot add detail or change the actual pixel count. A print application's scaling options can override that tag.
Common portrait print sizes at 300 PPI
| Size (inches) | Ratio | Pixels needed | Editor support |
|---|---|---|---|
| 4 × 6 | 2:3 | 1200 × 1800 | Within export cap; sufficient source pixels still required |
| 5 × 7 | 5:7 | 1500 × 2100 | 5:7 is not a supported crop preset |
| 8 × 10 | 4:5 | 2400 × 3000 | Within export cap; sufficient source pixels still required |
| 8 × 12 | 2:3 | 2400 × 3600 | Within export cap; sufficient source pixels still required |
| 9 × 12 | 3:4 | 2700 × 3600 | Within export cap; sufficient source pixels still required |
| 11 × 14 | 11:14 | 3300 × 4200 | Exceeds the 4096-pixel side cap |
| 12 × 18 | 2:3 | 3600 × 5400 | Exceeds the 4096-pixel side cap |
A4 (210 × 297 mm) at 300 PPI requires approximately 2480 × 3508 pixels. A3 needs approximately 3508 × 4961, exceeding this editor's 4096-pixel side cap. Rounded paper dimensions differ slightly from the ideal 1:√2 proportion: check the print shop's paper and bleed requirements.
Why a 4096 setting may not export 4096 pixels
It is a maximum, not an enlargement instruction. This editor does not upscale. A 1200 × 800 source has fewer usable pixels after cropping and cannot become a detailed 3600-pixel original. At 300 PPI, 1200 × 800 pixels corresponds to about 4 × 2.67 inches. Lower PPI allows a larger physical print, with results depending on the artwork, viewing distance and printing process.
Crop or resize the whole image?
- To fit a 4:5 frame, crop and check that text or faces are not cut off.
- To preserve the complete composition, resize the whole image without changing its proportions. Add borders elsewhere or ask your printer if needed.
- For multiple ratios, review and confirm every crop independently rather than assuming one position fits every frame.
Example: prepare 8 × 10 and 8 × 12 artwork files
- Start with a sufficiently large original you have the right to use.
- Select 4:5 and 2:3 in the editor and position each crop.
- Confirm and export; inspect each JPG's actual pixel dimensions, not just its filename or DPI tag.
- Calculate the effective PPI at the intended physical size, and confirm borders, bleed and colour proofing with the printer.
The tool exports JPGs, not print-layout PDFs or bleed-ready artwork. Browser colour conversion is not professional prepress colour management. A ZIP bundle is convenient packaging, not a guarantee of compatibility with every frame or print process.
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