Poster Sizes, Aspect Ratios and DPI
Before resizing, decide the physical print size and the printer's required resolution. The aspect ratio determines the shape; the pixel dimensions determine how much image information the file contains.
Calculate the pixel dimensions
Multiply each side in inches by the target pixels per inch. For centimetres, divide by 2.54 first. A 12 × 16 inch poster at 300 PPI needs 3,600 × 4,800 pixels. A 20 × 30 inch poster at the same resolution needs 6,000 × 9,000 pixels.
| Ratio | Example size | Pixels at 300 PPI |
|---|---|---|
| 2:3 | 12 × 18 inches | 3,600 × 5,400 |
| 3:4 | 12 × 16 inches | 3,600 × 4,800 |
| 4:5 | 16 × 20 inches | 4,800 × 6,000 |
| 1:1 | 12 × 12 inches | 3,600 × 3,600 |
Watch the live crop preview
WallArtReady's Resize tool previews the target shape and dimensions before you apply it. A change of ratio can crop edges. Keep titles, labels and artwork inside the safe area; if they do not fit, consider expansion or a different ratio.
High DPI does not automatically mean high quality
DPI describes printer dots, while PPI describes image pixels per printed inch. Image tools often label resolution settings as DPI. Neither label can restore missing detail by itself. Check the actual pixel dimensions, viewing distance and print provider's specification.
Open the artwork editor