Image DPI Changer

How to convert an image to 300 DPI online

What is DPI — and why it doesn't change your pixels

DPI (dots per inch) is a single metadata value that tells printers how densely to place your image's pixels on paper. A 3000×2000 px photo contains exactly the same pixels at 72 DPI and at 300 DPI — the only difference is the intended print size: 41.7×27.8 inches versus 10×6.7 inches.

That's why this image DPI converter never re-encodes your picture. It rewrites the resolution fields (JFIF & EXIF for JPG, the pHYs chunk for PNG) and leaves every pixel byte exactly as it was. Tools that "convert DPI" by re-saving the image quietly degrade quality — there is no reason to.

Print size at 300 DPI — quick reference

To print sharp at 300 DPI, your image needs roughly these pixel dimensions:

Drop an image into the tool above and it shows the exact print size at your chosen DPI automatically.

Image DPI calculator — pixels ⇄ print size

Use this quick image DPI calculator to see how large your photo will print, or how many pixels you need for a target print size.

Who needs a 300 DPI image?

Print shops and photo labs, academic journals and conference papers, Amazon KDP book covers and interiors, Etsy printables, embroidery and engraving services, passport and ID photo requirements, magazine ads — all of them routinely reject files whose DPI metadata isn't set to 300. Fixing it takes seconds here and costs nothing.

Common DPI requirements at a glance

Different platforms and print services ask for different resolution settings. These are the values you will most often be asked for:

When a submission form rejects your file for "low resolution", it is almost always this single metadata number — change the image DPI to the required value above and re-upload the very same picture.

Why print services reject files over one number

The rejection email rarely explains itself, so here is what actually happens on the other side, in the three places people hit it most:

At the print shop. Commercial printers run every order through preflight software before a human ever sees it. That software reads one field — the DPI metadata — to decide how large your file will print. A 3000 × 2400 px photo tagged 72 DPI claims it wants to print 41 inches wide; the system compares that against your ordered 10 × 8 in print, concludes the file is "low resolution", and bounces it. The pixels were enough all along — a 300 DPI tag makes the same file claim exactly 10 × 8, and preflight waves it through.

At the journal or conference. Publishers put "figures at 300 DPI minimum, 600 for line art" in their author guidelines because page layout happens months later, by someone who never saw your screen. The metadata is the only instruction that survives the hand-off: it tells the typesetter how big the figure can safely sit on the page. Submissions systems increasingly enforce it automatically — the manuscript uploads, the figure check fails, and the revision clock starts over a field you can edit in two seconds.

At the marketplace. Stock libraries, print-on-demand platforms and Etsy digital-download buyers all treat the DPI tag as a promise about print quality. A printable tagged 96 DPI collects "blurry when printed" reviews not because the pixels were bad, but because buyers' home printers obeyed the tag and stretched the image. Sellers who set 300 DPI before uploading are making the same file keep its promise.

In all three cases nothing about your actual image was wrong — the label was. That is the whole reason this tool exists: correct the label, keep every pixel byte-identical, and re-submit.

Changing image DPI without Photoshop

You can change DPI in desktop software, but every route is slower than a browser tool — and some quietly resample your pixels along the way:

Photoshop — Image → Image Size, untick "Resample", type a new resolution. Safe, but it needs a subscription and a download. GIMP — Image → Print Size, set the X and Y resolution. Free, yet a 200 MB install is overkill for a metadata edit. macOS Preview — Tools → Adjust Size can resample your image if the wrong boxes are ticked, silently changing your pixels. Windows — offers no built-in way to change DPI at all.

SetDPI performs the same lossless metadata edit in one drag-and-drop, with no install, no account and no upload — which is exactly why an image DPI changer belongs in the browser.

Frequently asked questions