Use pixels divided by inches
For a proportional image, width in pixels divided by printed width in inches gives pixels per inch, or PPI. Do the same for height. DPI is often used informally for this discussion, but a file label alone does not determine the detail available.
| Original image | Printed size | Effective resolution |
|---|---|---|
| 800 × 800 px | 4 × 4 in | 200 PPI |
| 800 × 800 px | 12 × 12 in | About 67 PPI |
| 3,000 × 1,500 px | 10 × 5 in | 300 PPI |
| 7,200 × 3,600 px | 96 × 48 in | 75 PPI |
A number is a check, not a quality guarantee
Small text and detailed logos usually need more source detail than a bold shape viewed from a distance. A large banner is not evaluated the same way as a small sticker held near your face. Inspect the actual artwork, viewing task and preview rather than treating one number as a universal pass.
If your image ratio differs from the selected print area, check Fit versus Fill. Cropping changes how much of the source contributes to the final view. Stretching introduces distortion and is not a resolution fix.
Improve the source instead of its label
Changing a file from 72 to 300 in a DPI field without adding genuine source detail cannot make a blurry logo sharp. Enlarging the pixel count may create a bigger file without recovering the original edges. Ask for the original design or export again from the editable source.
The current upload ceiling is 40 megapixels and 20 MB per artwork file. Do not export a huge banner at a blanket 300 PPI if it exceeds those limits. The calculator is a planning aid; the editor checks the actual file and the print preview remains essential.
Common questions
Is 300 DPI required for every product?
Do not apply that as a blanket rule, especially to large banners. Consider the physical size, artwork detail and viewing distance, then inspect the actual file within current upload limits.
Can I make a low-resolution file smaller?
Reducing its printed dimensions increases its effective PPI. It may be a useful choice if the smaller design still suits your item.