What 300 DPI actually means
DPI is dots per inch: how many pixels the printer squeezes into one inch of paper. 300 DPI is the standard for photos and cards held in the hand. A 4×6 in print needs 1200×1800 px; an A4 needs about 2480×3508 px.
DPI Checker & 300 DPI Converter
Drop an image to see how large it can print at 300 DPI, which common sizes pass, and what a print shop will complain about. Then export a lossless PNG with the right DPI tag.
Everything runs in your browser. Your file is never uploaded.
🖨️
Drop an image here or click to choose
JPEG, PNG, WebP or GIF · up to 80 MB
Pixels beat DPI tags
The DPI number stored in a file is just a label. A 1000 px image tagged 300 DPI is still 1000 px. Editors and print shops read the tag to decide the physical size, so a wrong tag causes wrong sizes, but only more pixels make a sharper print.
Why export PNG
JPEG throws away detail on every save and can carry a CMYK profile that some shops reject. PNG is lossless, always sRGB or gray, and stores the DPI tag in a standard chunk that every editor reads.
Common print sizes at a glance
Pixels needed for each size at 300 DPI (sharp) and 150 DPI (posters seen from a distance).
| Print size | At 300 DPI | At 150 DPI |
|---|---|---|
| 4 × 6 in · 10.2 × 15.2 cm | 1200 × 1800 | 600 × 900 |
| 5 × 7 in · 12.7 × 17.8 cm | 1500 × 2100 | 750 × 1050 |
| A5 · 14.8 × 21 cm | 1749 × 2481 | 875 × 1241 |
| 8 × 10 in · 20.3 × 25.4 cm | 2400 × 3000 | 1200 × 1500 |
| A4 · 21 × 29.7 cm | 2481 × 3507 | 1241 × 1754 |
| 11 × 14 in · 27.9 × 35.6 cm | 3300 × 4200 | 1650 × 2100 |
| A3 · 29.7 × 42 cm | 3507 × 4962 | 1754 × 2481 |
| 12 × 18 in · 30.5 × 45.7 cm | 3600 × 5400 | 1800 × 2700 |
| 18 × 24 in · 45.7 × 61 cm | 5400 × 7200 | 2700 × 3600 |
| 24 × 36 in · 61 × 91.4 cm | 7200 × 10800 | 3600 × 5400 |
Frequently asked questions
Does this tool upload my image?
No. The file is parsed and re-encoded entirely in your browser with the Canvas API. Nothing is sent to a server, so there is no size limit beyond what your browser can hold in memory.
My image is 72 DPI. Can I just change it to 300?
You can, and this tool does exactly that, but it only changes the label. If the image is 1000 px wide, it prints sharp at about 3.3 inches wide no matter what the tag says. For a bigger print you need more pixels, which is what the 4K upscaler is for.
Is 150 DPI good enough?
For a poster or banner viewed from a metre or more, yes. For photos, cards, book covers or anything held in the hand, aim for 300 DPI.
Do print shops need CMYK?
Most online photo and poster services accept sRGB and convert it themselves. Offset printing for packaging or magazines usually wants a CMYK file with a specific profile, which this tool does not produce. Ask the press for their spec.
Does the export change my colors or crop the image?
No. The PNG contains the same pixels at the same size. The only additions are the DPI tag and a lossless container.