Effective DPI
Will this image print clearly?
Effective DPI from real pixels and planned trim size. Files stay on your device.
Input
Image and planned print size
Choose an image first, or enter pixel width and height.
Or enter pixels directly—e.g. a phone photo at 4032 × 3024, no file needed.
Effective DPI
Effective DPI uses the lower of horizontal and vertical; it does not judge blur or upscaling.
Guide
Effective DPI bands
- ≥ 300 — Close, detailed print
- 200–299 — Most small prints
- 150–199 — Distance viewing or proofs
- < 150 — Shrink trim size or use a larger image
The DPI saved in a file is not the DPI you will print at
An image file stores a pixel count and, often, a DPI tag such as 72 or 300. The tag is only a label. What decides print quality is the effective DPI: pixels ÷ inches of printed size. A 3000 px wide photo is 300 DPI when printed 10 inches wide and only 100 DPI at 30 inches.
This checker reads the real pixel width and height from your file, divides each by the print size you enter (millimetres ÷ 25.4 gives inches), and reports the lower of the two results, because a mismatched aspect ratio can leave one axis softer than the other.
For a quick reference: 300 DPI or more suits close-up detailed print, 200–299 DPI suits most small prints, 150–199 DPI is fine for posters read from a distance or for proofs, and below 150 DPI you should shrink the trim size or use a larger image.
Minimum pixels
Pixels needed for common print sizes
The image size in pixels you need for each print size at three effective DPI levels. Width × height, rounded to whole pixels.
| Print size | Millimetres | 150 DPI | 200 DPI | 300 DPI |
|---|---|---|---|---|
| Passport photo | 35 × 45 | 207 × 266 | 276 × 354 | 413 × 531 |
| 4 × 6 in photo | 101.6 × 152.4 | 600 × 900 | 800 × 1,200 | 1,200 × 1,800 |
| 5 × 7 in photo | 127 × 177.8 | 750 × 1,050 | 1,000 × 1,400 | 1,500 × 2,100 |
| A5 | 148 × 210 | 874 × 1,240 | 1,165 × 1,654 | 1,748 × 2,480 |
| A4 | 210 × 297 | 1,240 × 1,754 | 1,654 × 2,339 | 2,480 × 3,508 |
| A3 | 297 × 420 | 1,754 × 2,480 | 2,339 × 3,307 | 3,508 × 4,961 |
| A2 poster | 420 × 594 | 2,480 × 3,508 | 3,307 × 4,677 | 4,961 × 7,016 |
| Business card | 90 × 54 | 531 × 319 | 709 × 425 | 1,063 × 638 |
How to check the DPI of an image
Three steps, no upload: your image is read inside the browser and never sent anywhere.
- Drop, paste or choose an image (JPG, PNG, WebP and other formats your browser can open), or type the pixel width and height yourself.
- Enter the size you plan to print at, or pick a preset such as A4 or 4 × 6 in.
- Read the effective DPI and its band. If it is too low, shrink the print size or find a larger image.
To see what your computer says about a file:
Windows. Right-click the file → Properties → Details. Dimensions shows the pixels; the resolution fields show the stored DPI tag, which is not the effective DPI.
macOS. Open the image in Preview → Tools → Adjust Size. It shows pixel dimensions and the stored resolution.
Photoshop and GIMP. In Photoshop open Image → Image Size and untick Resample; in GIMP use Image → Print Size. Changing the resolution there changes the print size, not the pixels.
What about the DPI of a PDF?
A PDF does not have one DPI. Text and vector artwork stay sharp at any size; only raster images placed inside the PDF have a resolution, and each has its own effective DPI: its pixels ÷ the size it is placed at.
This tool checks single image files and does not read PDFs. To check a picture used in a PDF, take the original image file and enter the size at which it is placed on the page. To audit every image in a finished PDF at once, use a preflight tool such as the one in Adobe Acrobat.
FAQ
Notes
How do I check the DPI of an image online?
Drop the image into the checker, enter the size you will print it at, and read the effective DPI. The file is read in your browser and is not uploaded.
What DPI do I need for printing?
300 DPI for close-up detailed prints such as photos and brochures, 200 DPI is enough for most small prints, and 150 DPI works for posters viewed from a distance. These are effective DPI at the final printed size.
Can I just change the DPI to 300 in the file properties?
Changing the tag does not add detail. It only changes the size the program assumes. What matters is whether the pixel count divided by the print size reaches the DPI you need.
Can this tool check the DPI of a PDF?
No. It reads image files only. A PDF has no single DPI; only the images placed inside it do. Check the original image with the size it is placed at, or use a preflight tool for a whole PDF.
What is the difference between DPI and PPI?
PPI counts pixels per inch in a digital image; DPI counts ink dots per inch a printer lays down. In everyday use, including print requirements like 300 DPI, people mean the same thing: pixels available per inch of printed size.
Tagged 72 DPI—unprintable?
Check real pixels vs trim size. Enough pixels can still hit 300 effective DPI when printed smaller.
Upscale until DPI looks fine?
Interpolation does not restore detail. Proof at final size.
Why the lower axis?
Mismatched aspect ratios can differ by axis; the lower value is safer.