A 24-megapixel portrait against each target
| Target | Needs at 300 DPI | Fits at | Outcome |
|---|---|---|---|
| A4 | 2480 × 3508 | 483 DPI | retag only |
| A5 | 1748 × 2480 | 686 DPI | retag only |
| A3 | 3508 × 4961 | 342 DPI | retag only |
| US Letter | 2550 × 3300 | 470 DPI | retag only |
| 4 × 6 in photo | 1200 × 1800 | 999 DPI | retag only |
| 5 × 7 in photo | 1500 × 2100 | 800 DPI | retag only |
| 8 × 10 in | 2400 × 3000 | 500 DPI | retag only |
| 12 × 18 in frame | 3600 × 5400 | 333 DPI | retag only |
| 50 × 70 cm frame | 5906 × 8268 | 203 DPI | lower DPI |
Limits
- Enlarging adds pixels, not detail; the Scale panel states the share that is interpolated.
- Colour is not converted for a press. A CMYK file is warned about before any resample, and the tag-only path keeps its data byte for byte.
Questions
Does my photo need resizing to print on A4?
Often not. If the pixels already cover A4 at the resolution you want, only the resolution tag has to change — and that is a rewrite of one field, with every pixel copied through. The panel says which of three cases you are in before anything is rendered.
What are the three outcomes?
The pixels already support the size at the requested resolution (change only the tag); they support it at a lower resolution (shown with its print tier, retag or enlarge); or they fall short of the 150 DPI floor (the shortfall in pixels, the largest size they do support at your resolution, and an enlarge-anyway option that says how much of the result is interpolated).
Why does my print come out with white bars?
Because the picture and the paper are different shapes. A 3:2 photograph on A4 (1.414:1) at full width is shorter than the sheet. The panel states it in centimetres; nothing is cropped unless you choose Fill the sheet.
Is 300 DPI necessary?
For prints held in the hand, 300 DPI is the figure most vendors state. Photo books are fine from about 240, and wall pieces viewed from a distance from about 150. The panel names the tier the achieved resolution falls in.
Does a frame size print the whole picture?
A mount or mat narrows the visible window. For a framed print, measure the opening and use that size, or leave a margin when you fill the sheet.
Neighbouring measurements
Only want the table of sizes at each DPI? The print size calculator works without a file.
- Print size calculatorPixel dimensions, centimetres, inches and density kept visibly linked.
- 300 dpiThe number a print vendor asks for, written into the file.
- Change DPIRewrite the density tag without touching a pixel.
- Upscale an imageEnlarge through a named kernel, with the share of computed pixels stated.
