DPI & Print Size Calculator
Enter your photo's pixel dimensions and the print size to get its DPI and print quality, or enter only a print size to see the pixels you need at 300 DPI. Calculations and the DPI changer below run entirely in your browser; no file is uploaded to a server.
Pick a print size or type one in. Results update as you type.
Print resolution of your photo
Pixels needed for this print size
| Resolution | Width × height (px) |
|---|
Largest print from this photo
Change the DPI of a JPG without re-compressing
Some forms and print shops ask for a "300 DPI" file and reject photos whose metadata says 72 DPI, even when there are plenty of pixels. Choose a JPG below and the tool saves a copy with only the DPI value in the file header (JFIF and EXIF resolution) changed. The image itself is not re-compressed, and the file never leaves your browser.
The DPI value only tells software how large to print the image; it doesn't change the pixel count or quality. Files saved by Photoshop also store a separate resolution that Photoshop may keep showing.
How DPI, pixels and print size relate
DPI (dots per inch; strictly PPI, pixels per inch, for digital images) is the number of pixels printed across one inch (25.4 mm). The math is simple:
- DPI = pixels ÷ print size in inches (inches = cm ÷ 2.54)
- Pixels needed = print size in inches × target DPI
A 4×6 inch print at 300 DPI needs 4 × 300 = 1200 by 6 × 300 = 1800 pixels. A 2×2 inch US passport photo at 300 DPI is exactly 600×600 pixels, the minimum the State Department accepts for digital photos. A full US Letter page (8.5×11 in) needs 2550×3300 pixels, and A4 (210×297 mm) about 2480×3508.
The DPI number stored in a file (72, 96, 300…) is just a label. A 3000×4000 pixel photo has the same quality whether it says 72 or 300; the real DPI is decided by the size you print it at, using the formula above.
Print quality guide
| Actual DPI | Rating | What to expect |
|---|---|---|
| 300 or more | Excellent | The standard for photo prints, passport photos and books. No visible pixels even up close. |
| 200–299 | Good | Fine for everyday prints and documents; may look slightly soft up close. |
| 150–199 | Fair | OK for posters viewed from a few feet away, a bit low for photo prints. |
| Under 150 | Poor | May look blurry or pixelated. Print smaller, or shoot or scan the original at a higher resolution. |
Large banners are seen from far away, so around 100 DPI is often enough. Passport photos are small and examined closely, so aim for 300 DPI.
Passport and visa photo sizes
| Document | Print size | Pixels | Notes |
|---|---|---|---|
| US passport (printed) | 2×2 in (51×51 mm) | 600×600 at 300 DPI | Head 1–1⅜ in (25–35 mm) from chin to top of head, plain white or off-white background |
| US visa / DV Lottery (digital) | Square | 600×600 to 1200×1200 | JPEG, 240KB or smaller |
| UK passport | 35×45 mm | Digital: at least 600×750 | Digital file 50KB–10MB |
| Schengen visa and most EU passports | 35×45 mm | 413×531 at 300 DPI | Face 70–80% of the photo height (ICAO standard) |
| Canadian passport | 50×70 mm | 591×827 at 300 DPI | Face 31–36 mm from chin to crown |
Sources: U.S. Department of State passport photo and digital image requirements (travel.state.gov), GOV.UK (Photos for passports) and Government of Canada passport photo guidance, checked October 2026. Rules change, so confirm with the issuing authority before you submit.
Frequently asked questions
How do I find a photo's size in pixels?
On Windows, right-click the file, choose Properties, then Details. On a Mac, select the file and choose Get Info. On a phone, open the photo and tap the info (ⓘ) button. A standard iPhone photo is 4032×3024 pixels; newer models can save 24-megapixel photos at 5712×4284.
Are my files uploaded?
No. The calculator only uses the numbers you type, and the DPI changer edits a few header bytes of your JPG inside the browser and saves the copy to your device. Nothing is sent to a server.
My photo doesn't have enough pixels. Can I just enlarge it?
You can reach the pixel count on paper, but enlarging doesn't add real detail. If a site asks for exact pixel dimensions, use resize image; if it also limits the file size, finish with the image compressor.