Free image DPI converter

1. Drop in your JPG or PNG. The tool reads the file's existing DPI tag automatically — for JPG that's the JFIF density field, for PNG it's the pHYs chunk — and shows you the pixel dimensions alongside it.
2. Pick a target DPI. Use a preset chip (72, 96, 150, 300, or 600) or type a custom value. 300 DPI is the standard for professional printing.
3. Convert. The tool patches the DPI metadata directly in the file's bytes. Your image pixels are never decoded, resampled, or re-compressed — only the DPI tag changes.
4. Download. Grab the converted file with the same resolution and the same visual quality, just a new DPI value baked into the header.

People use “DPI” and “resolution” interchangeably, but they describe two completely different things, and mixing them up is the single most common source of confusion about image quality.

Resolution is the actual pixel count of an image — for example 3000×2000 pixels. This is the real data: every pixel holds color information, and resolution determines how much detail an image can possibly contain. Resolution is fixed the moment an image is captured or rendered, and it only changes if you resample the image (resize it up or down), which is a real, lossy or interpolated pixel operation.

DPI (dots per inch, sometimes called PPI — pixels per inch) is not a property of the image data at all. It's a single number stored in the file's metadata that tells a printer or a layout program “when you print this, pack this many pixels into every inch.” DPI is purely an instruction for physical output size. It does not add or remove a single pixel, and it has zero effect on how the image looks on a screen, in a browser, or in an app — screens don't read the DPI tag at all, they just display every pixel 1:1 (or scaled by your OS/browser zoom).

That's exactly why this tool can “convert DPI” instantly with zero quality loss: changing DPI is a one-field metadata edit, not an image-processing operation. If you actually need to change the pixel count — to make an image sharper at a given print size, or to shrink a file — you need to resample it with our image resizer, which is a genuinely different operation from what this tool does.

Once you know that DPI is just an instruction, the print size formula is simple division:

print size (inches) = pixel dimension ÷ DPI

For example, a photo that is 3000×2000 pixels, printed at 300 DPI, comes out to:

3000 ÷ 300 = 10 inches wide
2000 ÷ 300 = 6.67 inches tall
→ 3000×2000px @ 300 DPI = 10×6.67 in (25.4×16.9 cm)

Take that exact same image and stamp it at 72 DPI instead, and the math changes even though the pixels didn't:

3000 ÷ 72 = 41.67 inches wide
2000 ÷ 72 = 27.78 inches tall
→ the same file now claims to print at 41.67×27.78 in

Nothing about the image changed — same file, same pixels, same on-screen sharpness. Only the number a print-layout program (InDesign, Photoshop, Canva, a photo-lab uploader) reads to decide how big to place it on paper changed. This is exactly what the tool above does: it lets you pick which of those two numbers — 10×6.67 in, or 41.67×27.78 in, or anything else — the file reports, without resampling a single pixel.

300 DPI is the print industry's default because it sits right at the edge of what the human eye can resolve at normal reading distance (roughly 12 inches / 30 cm). Print professionally, and most print shops, photo labs, and prepress checklists will explicitly ask for 300 DPI:

• Business cards, flyers, brochures: viewed up close, so anything under 300 DPI shows visible softness or pixelation once ink hits paper.
• Photo prints and canvas: 300 DPI (or 240–300 DPI for larger canvas prints viewed from further away) keeps skin tones and fine detail crisp.
• Book interiors and magazines: commercial presses are calibrated around 300 DPI source images; lower DPI often gets flagged in a prepress check.
• Large-format posters and banners: viewed from farther away, so 150 DPI is often acceptable and keeps file sizes manageable — 300 DPI on a poster-sized canvas can produce enormous files for no visible benefit.

The important caveat: setting the DPI tag to 300 does not make a low-resolution image print sharp. If your photo is only 900×600 pixels, tagging it at 300 DPI just makes it report a 3×2 inch print size — it does not invent detail that was never captured. DPI conversion changes what a program thinks the print size should be; it cannot add missing pixels. For that, you need genuine upscaling, not a metadata edit.

You will still see plenty of advice online insisting that “web images should be 72 DPI” and “Windows uses 96 DPI.” Both numbers are historical relics, and neither one matters for how an image looks in a browser today.

Where 72 DPI came from: the original 1984 Apple Macintosh had a 72-pixel-per-inch screen, chosen so that one point in a page layout (1/72 of an inch, a unit from print typography) mapped to exactly one screen pixel. That made on-screen WYSIWYG page design easy on that specific hardware. Early web designers, coming from print and Mac backgrounds, carried the “72 DPI for web” convention forward — even though it stopped being physically meaningful the moment screens moved past 72 actual pixels per inch.

Where 96 DPI came from: Windows adopted 96 DPI as its default display scaling reference in the early 1990s, again as an assumption baked into the OS rather than a measurement of any real monitor.

Why neither matters now: web browsers, phones, and every modern operating system render images using their actual pixel dimensions, not the DPI metadata tag. A 1200×800px PNG displays identically in a browser whether its DPI tag says 72, 96, 300, or is missing entirely — browsers simply don't read it for on-screen rendering. Actual screen sharpness today depends on the screen's real pixel density (a 4K monitor might be 140–220 real PPI; a phone display can exceed 400 PPI) and CSS/device-pixel-ratio scaling, none of which the embedded DPI tag controls.

The one place the 72/96 DPI convention still has a shred of relevance is compatibility: some older software or automated print/upload pipelines check for a DPI value and misbehave if the field is completely absent, or some legacy tools display “image info” panels that show the tag and confuse users who assume it affects screen quality. If a workflow specifically demands a DPI value be present, this tool lets you set it without changing anything about how the image actually looks.

• Sending a photo to a print shop or photo lab that rejects uploads without a 300 DPI tag, even though the pixel count is already sufficient.
• Placing an image in InDesign, Photoshop, Illustrator, or Canva and wanting the placed-image size to default to the right physical dimensions without manually typing width/height every time.
• Satisfying a submission requirement — stock photo sites, print-on-demand platforms, and some publishers explicitly require a minimum DPI tag on upload.
• Fixing a missing or incorrect DPI tag from a scanner, camera, or export tool that left the field blank, which some software defaults to 72 DPI and misreports as “low quality.”

If instead your actual pixel dimensions are too small for the print size you need, DPI conversion won't help — you need to resample with our image resizer (which will introduce some upscaling softness, since it's creating new pixel data), or re-shoot/re-scan at a higher native resolution.

Yes. This tool reads and rewrites metadata bytes entirely inside your browser — it never uploads your images to a server. For JPG files it locates and rewrites the JFIF APP0 density field; for PNG files it inserts or replaces the pHYs chunk with a freshly computed CRC32 checksum so the file stays valid. Because your pixel data is never decoded or re-encoded, there is no generational quality loss, no recompression artifacts, and no risk of the tool silently resizing your image. It works offline once the page has loaded, and nothing is stored or logged.