The numbers this route keeps in agreement
Physical size is not stored as a second image. It is the pixel count divided by a density: 3000 pixels at 300 dots per inch occupies ten inches; the same 3000 pixels at 150 occupies twenty. Nothing about the recorded detail changes between those two statements.
The useful question is therefore not whether a file is '300 DPI' in isolation, but whether it contains enough pixels for the intended width at that density. This panel keeps the stored field and the achievable size side by side so an administrative requirement cannot hide the arithmetic.
What cannot be solved by changing a field
- A metadata edit can satisfy a field check and still fail an effective-resolution check after the image is enlarged in a layout.
- Resampling upward creates a denser grid by interpolation; it does not turn an out-of-focus or compressed source into new recorded detail.
Questions about scale and density
How big can I print a 3000 × 2000 pixel photo?
At 300 dpi, 25.40 × 16.93 cm (10 × 6.67 in). At 150 dpi, twice that on each side. The pixels do not change between those answers; the density decides how far apart they are laid down on paper.
What DPI do I need for a good print?
Around 300 for prints viewed at arm's length, 150–200 for posters seen from further back. The verdict line under the fields says how the current density will read, and it is a guide rather than a rule: viewing distance matters more than the number.
Does this calculator change my file?
Only if you export. In print-size-only mode the export rewrites the resolution tag and copies every pixel through untouched. Without a file open, the panel is a calculator and nothing is written.
Why do two applications show different print sizes for the same file?
A JPEG can state its resolution in two places, the JFIF header and the Exif block, and applications disagree about which one to believe. If the two differ, the file opens at two sizes. Writing here sets both, to the same figure.
Can I type the size and get the DPI?
Yes. In print-size-only mode the pixels are fixed, so typing a width in centimetres computes the density that makes it, and the export writes that density.
Use the neighbouring measurement when needed
- 300 dpiThe number a print vendor asks for, written into the file.
- Change DPIRewrite the density tag without touching a pixel.
- Image resamplingA percentage-led pixel resize with the interpolation cost stated before export.
- DPI is metadata, not detailWhat the number in the file describes, and what it does not.
