How does the print size checker work?
You drop in one photo — JPEG, PNG or WebP. The checker reads its true pixel measurements (a portrait phone photo stored sideways is turned upright first, so it is measured the way you see it), and then computes, for every common print size, the one number that decides the print: effective DPI — how many of your pixels land on each inch of paper after the centre crop that print’s shape needs.
Each size gets one of three verdicts:
| Verdict | Effective DPI | What it means |
|---|---|---|
| Sharp | 300 and up | Crisp even with your nose close to it |
| Good | 200 – 299 | Looks good on the wall and in an album |
| Soft | below 200 | Visibly blurry at reading distance |
One honest footnote from the photo labs’ own standards (CEWE, Shutterfly, Mpix, read September 2026): a poster viewed from about a metre away still looks good from 150 DPI, because your eye cannot resolve more detail at that distance. That is why big prints are more forgiving than small ones — the opposite of what most people expect.
What pixels does each print size need?
For a Sharp print at 300 DPI, computed from the sizes themselves (inches × 300, September 2026):
| Print size | Shape | Pixels for Sharp (300 DPI) |
|---|---|---|
| Wallet (2 × 3 in) | 3 : 2 | 600 × 900 |
| 4 × 6 in | 3 : 2 | 1200 × 1800 |
| 5 × 7 in | 7 : 5 | 1500 × 2100 |
| 8 × 10 in | 5 : 4 | 2400 × 3000 |
| 8 × 12 in | 3 : 2 | 2400 × 3600 |
| A4 (8.3 × 11.7 in) | √2 | 2480 × 3508 |
| 11 × 14 in | 14 : 11 | 3300 × 4200 |
| 16 × 20 in | 5 : 4 | 4800 × 6000 |
| Poster (20 × 30 in) | 3 : 2 | 6000 × 9000 |
A 12-megapixel phone photo (about 4000 × 3000 pixels) is Sharp through 8 × 10, Good at 11 × 14, and Soft on a 16 × 20 — still fine for a poster on the wall, per the 150-DPI footnote above.
Why does an 8 × 10 print crop my photo?
Shape, not size. A 4 × 6 print has the same 3 : 2 shape as most cameras save, so nothing is lost. An 8 × 10 has the squarer 5 : 4 shape, so the lab keeps the middle of the photo and trims the sides: on a 3 : 2 photo, that is about 17 % of the picture gone. Every row in the verdict table names this crop loss, and the preview draws the dashed 8 × 10 frame on your photo so you can see exactly what survives.
If a size would crop away more than half your photo — a panorama printed on 8 × 10, say — the table says so, and a custom print size that keeps your photo’s own shape is the better choice.
What the checker will not do
- It does not add pixels. A print bigger than your pixels allow turns out soft; no setting here changes that. If every verdict says Soft, the photo is a thumbnail or a small copy from a website, and the only honest fix is going back to the original file.
- It refuses huge files above 50 megapixels by naming the file’s true size — a measurement this big can run a browser out of memory. Your photo is fine; make a smaller copy and check that.
- Apple HEIC photos are not read here — convert one first on the HEIC to JPG page (free, in your browser), then drop the JPG in.
Everything runs on your device: the measurement, the crop preview and the one-page print plan PDF you can download — a sheet with your verdict table, the pixels each size needs, and the 8 × 10 crop, dated for the trip to the lab or the drugstore photo counter.
Next steps
- Need different pixels for a size you settled on? Resize the image — the A4-at-300-DPI size is one click.
- Sharing a photo publicly? Check what metadata it carries first — GPS coordinates included.
- Turning photos into things to print: a photo calendar or a tidy photo album PDF, all in your browser.
Questions
How big can I print my photo?
Drop it in above and read the table — that answer depends on your photo's pixels, not on a rule of thumb. As a guide: your photo's long side in pixels, divided by 300, is the longest print in inches that stays sharp. A 3000 × 2000 photo gives 10 inches; the checker names the exact size for your file.
What DPI do I need for an 8 × 10 print?
300 DPI for a sharp print you hold in your hand, which means 2400 × 3000 pixels. From 200 DPI (1600 × 2000 pixels) it still looks good; below 200 it turns visibly soft. The checker shows your photo's effective DPI for every size, after the crop.
Why does an 8 × 10 print crop my photo?
Because of shape, not size. Most cameras save photos in the 3 : 2 shape of a 4 × 6 print, but an 8 × 10 is the squarer 5 : 4 shape. Something has to give: the lab keeps the middle and trims the sides — on a 3 : 2 photo that is about 17 % of the picture. The checker shows this crop loss for every size, and the dashed frame in the preview shows exactly what an 8 × 10 keeps.
Does the DPI stored in my photo's file matter?
No. That tag is a printing suggestion the camera wrote into the file — it says nothing about how many pixels your photo actually has, and only pixels count. Two copies of the same photo tagged 72 DPI and 300 DPI print exactly the same. This checker ignores the tag on purpose and measures the pixels.
Can I print bigger than the checker says?
You can always print bigger — it just gets softer, because the pixels cannot be stretched into detail that is not there. Posters are the honest exception: a poster hangs on a wall and is viewed from about a metre away, so from around 150 DPI upwards it still looks good. What no tool can honestly do is add pixels: making a small photo bigger does not make it sharper.
Are my photos uploaded anywhere?
No. The photo is read in your browser, the verdicts are computed on your device, and the print plan PDF is built there too. No request carries your photo anywhere, and closing the tab erases everything.