Image DPI checker and changer
Drop in a PNG or JPG to see its pixel size, the DPI stored in the file and the largest size it will print well, then download a copy with the DPI you need.
Image DPI checker and changer
Choose an image and you'll see its DPI and print size here.
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What changing the DPI does, and what it doesn't
An image is a grid of pixels. The DPI saved in the file only tells printers and design apps how many of those pixels to put in each inch. A 3000 px wide image saved at 300 DPI opens 10 in wide, and the same pixels saved at 72 DPI open almost 42 in wide.
So changing the DPI here doesn't make the image sharper or blurrier. Every pixel stays exactly the same. It only changes the size the file opens at, which matters for print shops, print on demand sites and Etsy buyers who check for 300 DPI.
For a sharp print at a given size you need enough pixels. Check the largest sharp print size above. If it is too small, start from a bigger original or upscale the image.
The file is read and changed in your browser. It is never uploaded, so this works for client work and unreleased designs too.
What DPI means for a digital file
A digital image has no physical size. It has pixels, for example 3000 across and 2400 down, and the pixel count alone decides how much detail it holds.
DPI (strictly PPI, pixels per inch, though nearly every program uses the two terms as if they were the same) is one number written into the file. It tells software how many of those pixels to fit into one printed inch.
That number is metadata. Change it from 72 to 300 and the image keeps every pixel it had. The only thing that changes is the instruction to the printer: the same 3000 pixels now cover 10 inches instead of almost 42.
Most of the confusion around DPI starts here. People treat the number as a quality setting, so they go looking for a way to raise it. Print quality is limited by pixels. The DPI tag only decides how those pixels get spread across paper.
Why your file shows 72 DPI
Open a phone photo, a screenshot or an export from a browser-based design app and you’ll often find 72 or 96 stored inside, or no value at all. Those defaults go back to old screen standards (72 for early Macs, 96 for Windows) and tell you nothing about how good the image is. A 4000 pixel wide phone photo tagged 72 DPI holds exactly as much detail as the same photo tagged 300.
The low number still causes real problems. Some print shops and upload forms read the stored value and reject anything under 300 without looking at the pixels. Some layout programs place a 72 DPI image at a huge physical size, so you end up shrinking it by hand every time you drop it into a document. Fixing the tag once, before the file goes anywhere, saves you both headaches.
How to check image DPI
Click the upload box or drag a PNG or JPG onto it. The tool reads the file and shows four things:
- The pixel size, width by height.
- The DPI stored in the file, or a note that none is stored.
- The print size that stored DPI produces.
- The largest good print size, worked out from the pixels at 300 DPI.
The last figure is the useful one. The stored DPI only tells you what someone typed into the file at some point. The largest good print size tells you how big you can actually go before the print starts to look soft up close.
Your browser reads the file on your own computer. Nothing is uploaded to a server, so client work and unreleased designs stay with you. You can test this yourself: load the page, switch off Wi-Fi, and run a file through it. It still works, because there was never anything to send.
How to change DPI online
Type the DPI you want, usually 300, and download the new copy. The tool writes the new value into the DPI field of the file (the pHYs chunk in a PNG, the density fields in a JPG header) and leaves the pixels alone. Width and height stay the same. The file size moves by a few bytes, if at all.
Your original file is untouched. You get a second file with the new setting, so if you change your mind you still have the version you started with.
Convert image to 300 DPI: what actually happens
This is the most common search around the topic, and it hides two very different situations.
In the first, the image already has enough pixels for the size you want to print. A 3000 by 2400 pixel image tagged 72 DPI is ready for a 10 by 8 inch print. All it needs is the correct tag, and changing it to 300 takes a second.
In the second, the image is too small. Take a 1200 by 800 pixel file. Tag it 300 DPI and the real print size becomes 4 by 2.67 inches. If you need it at 8 by 10, retagging won’t get you there, because the detail for that size was never captured.
The only route is upscaling, which means software invents new pixels between the real ones. AI upscalers do a far better job of this than the old bicubic resize in image editors, but the results depend heavily on the image. Text, faces and fine line art go wrong first.
This tool doesn’t upscale, on purpose. A file stamped 300 DPI that prints blurry is worse than one that tells you plainly it’s only good for 4 by 6.
Check the largest good print size first. If it’s smaller than what you need, you know the fix is a bigger source file or an upscaler, and the DPI field won’t help either way.
How big can you print?
The maths is one division. Pixels divided by DPI gives you inches. Multiply inches by 2.54 for centimetres.
At 300 DPI, these are the pixel sizes you need for common print sizes:
| Print size | Pixels needed at 300 DPI |
|---|---|
| 4 × 6 in | 1200 × 1800 |
| 5 × 7 in | 1500 × 2100 |
| 8 × 10 in | 2400 × 3000 |
| US Letter (8.5 × 11 in) | 2550 × 3300 |
| A4 (210 × 297 mm) | 2480 × 3508 |
| 11 × 14 in | 3300 × 4200 |
| A3 (297 × 420 mm) | 3508 × 4961 |
| 16 × 20 in | 4800 × 6000 |
| 18 × 24 in | 5400 × 7200 |
300 is the standard for anything people hold in their hands: photo prints, cards, planner pages, worksheets. It isn’t a law of physics.
A poster on a wall gets looked at from a metre or two away, and at that distance 150 to 200 DPI usually prints fine. A banner seen from across a room can go lower still. If a file comes up a little short of 300 for a wall piece, don’t panic. If it comes up short for a greeting card, take it seriously.
A worked example
You have a landscape phone photo, 3600 by 2400 pixels. The tool shows a stored DPI of 72, which would make it 50 by 33.3 inches on paper. That number is meaningless for printing, and it’s exactly what trips up layout software.
The largest good print size reads 12 by 8 inches. That’s the real answer.
You want it on A4 in landscape, which is 11.69 by 8.27 inches. The photo is a 3:2 shape and A4 is a little squarer, so to fill the sheet you scale it to the height: 2400 pixels over 8.27 inches comes to about 290 pixels per inch, with a sliver cropped from the left and right edges. That’s close enough to 300 that nobody will see the difference.
Set the DPI to 300, download, and send the new file to the printer. It now opens at 12 by 8 inches instead of 50 by 33, and any upload form that checks for 300 lets it through.
Before you upload to a marketplace or printer
If you sell printables or print-on-demand designs, run every file through a check like this before it goes up. Two things are worth confirming each time. First, that the pixel size covers the largest size you’re offering, using the table above.
Second, that the stored DPI matches what you claim in the listing, because buyers who open the file in an image editor will see that number before anything else.
A file tagged 72 DPI gets refund requests from customers who don’t know the tag is cosmetic. A file tagged 300 but only has pixels for a postcard gets worse ones. Both take ten seconds to catch here, so bookmark the page and make it the last step before every upload.
Print shops are the other place this pays off. Many of them check the DPI field automatically on upload. Getting a file bounced back the evening before a deadline costs a lot more time than checking it first.
Frequently asked questions
Does changing DPI reduce image quality?
No. The tool only rewrites the DPI value and doesn’t touch the pixels, so the image is identical. What changes is the size the file asks to be printed at.
Will I see a difference on screen between 72 and 300 DPI?
No. Screens ignore the DPI tag and show images pixel for pixel. Two copies of the same image tagged 72 and 300 look exactly alike on any monitor or phone.
Do I always need 300 DPI?
For prints people hold close, yes, aim for 300. Posters and wall art viewed from a distance usually print well at 150 to 200. For anything that stays on a screen (social posts, website images, digital wallpapers) DPI doesn’t matter at all and only pixel size counts.
Why does my phone photo show 72 DPI?
Phones and many apps write a default value of 72 or 96 that dates back to old screen standards. It has no link to the photo’s quality. Check the pixel size instead.
Which file types does the tool accept?
PNG and JPG. If you have a WebP, HEIC or TIFF file, convert it to PNG or JPG first, then run it through the checker.
Is my image uploaded anywhere?
No. Your browser reads the file locally and builds the new copy on your device. Nothing is sent to a server and nothing is stored after you close the page.
Can I make a small image print large by setting a higher DPI?
No. A higher DPI makes the stated print size smaller, not sharper. To print a small image large you need more pixels, which means a bigger original or an upscaler.