Processed entirely on your device — nothing is uploaded
How to use the dpi converter
- 1Drop in a JPG or PNG — the tool reads and shows its current DPI, if any.
- 2Pick the target: 300 DPI covers most government-form requirements; 200 and 600 have their own presets.
- 3Check the print-size line to see what the new DPI means physically.
- 4Download — same pixels, same quality, new DPI tag, with the value in the filename.
What DPI actually is — and why changing it is legitimate
DPI (dots per inch) is not a property of your pixels; it is an instruction about printing them. A 1200 × 1500 pixel photo is the same photo at 300 DPI (printing 4 × 5 inches) and at 150 DPI (printing 8 × 10) — the tag tells software how densely to lay the same pixels on paper. That is why this tool can change DPI without touching image quality: it edits the instruction, not the picture.
In a JPG the instruction lives in the JFIF header's density fields; in a PNG it is the pHYs chunk, stated in pixels per metre. Many files — screenshots, WhatsApp downloads, some phone photos — carry no density information at all, which readers display as '96 DPI' by convention. The tool shows you exactly what your file carries before it changes anything.
Changing the tag is not a trick; it is the correct fix. When a form says '300 DPI', it is specifying intended print density, and a file whose metadata says so — with enough pixels for the size being printed — is precisely compliant. What the tag cannot do is invent detail, which is the honest limit covered below.
The forms that ask, and what they are really checking
Indian government portals are the main source of DPI requirements: passport and visa photo uploads, property and land-registry document scans, court e-filing systems, and various certificate-upload forms specify 200, 300 or 600 DPI. Their validators read the metadata fields this tool writes — which is why a perfectly sharp photo gets rejected for 'incorrect DPI' when its tag says 96 or nothing at all.
The pixel arithmetic behind the print-size line: physical size equals pixels divided by DPI. A 600 × 600 photo at 300 DPI prints 2 × 2 inches; the same pixels tagged 200 DPI print 3 × 3. When a form specifies both a physical size and a DPI, multiply them to get the pixels it expects — 3.5 × 4.5 cm at 300 DPI is 413 × 531 — and use the Passport Photo Maker or Image Resizer to hit the pixel count first, then this tool for the tag.
Scanners set DPI honestly at capture time, which is why 'scan at 300 DPI' beats rescaling later. But when the document is already scanned and only the tag is wrong, retagging here is exactly equivalent to what re-scanning at the right setting would have produced — same pixels, correct label.
What retagging cannot do
Raising DPI does not add detail. If a form demands an A4 scan at 300 DPI — roughly 2480 × 3508 pixels — and your file is 800 × 1100, tagging it 300 DPI produces a file that prints A4-sized only at visibly low sharpness, and validators that check pixel counts will still refuse it. The tag and the pixels must both satisfy the spec; this tool fixes the tag, the Image Resizer fixes the count.
Nor does DPI affect on-screen appearance or file size in any meaningful way: screens ignore the tag entirely, and the rewrite here changes a handful of metadata bytes, leaving compression untouched. If the portal also caps the file size in KB, the compress-to-size pages on this site handle that step — after this one, since re-encoding may rebuild the header.
Everything happens in your browser at the byte level: the file is parsed, the density fields rewritten, and the download assembled locally. Documents headed for a land registry or a court are exactly the kind of thing that should not transit a stranger's server, and here they do not.
Frequently asked questions
How do I change a photo to 300 DPI?
Drop it in, keep the 300 preset, download. The pixels are untouched — only the JFIF (JPG) or pHYs (PNG) metadata changes, which is the field form validators read.
Does increasing DPI improve image quality?
No — DPI is a print-density label, not detail. Quality lives in the pixel count. Retagging satisfies forms that check the label; if a form also requires more pixels than you have, only re-scanning or a larger original genuinely helps.
Why does my file show 'none set' as its current DPI?
Many files — screenshots, messaging-app downloads — carry no density metadata, and software just assumes 96. That assumption is exactly what fails a 300 DPI check; writing a real value fixes it.
Will the file size or quality change?
Effectively no — the image data is copied byte-for-byte; only a few header bytes change (a file with no header gains about 18 bytes). There is no recompression, so quality is mathematically identical.
What about WebP or HEIC files?
Convert them to JPG or PNG first with the Image Converter or HEIC tool on this site — DPI requirements come from forms that expect those two formats anyway.
Is my document uploaded?
No — the bytes are edited in your browser's memory and downloaded straight back. Nothing is transmitted, which matters for the identity documents this tool usually handles.