Will converting to 300 DPI make my photo look better?

No. The pixels are untouched, so on screen the image is identical. It will print smaller and therefore sharper, because the same detail is packed into a smaller area — but no detail is added.

My form says '300 DPI minimum' but still rejects my file. Why?

Almost always because it is checking pixel dimensions, not the DPI tag. A 400 × 500 photo tagged 300 DPI is still a 400 × 500 photo. Compare your image against the table above for the size you need.

Does changing the DPI change the file size?

Only by a few bytes. The tag is a handful of numbers in the file header; no image data is re-encoded, so nothing is recompressed and nothing is lost.

Should I use 600 DPI instead?

Only if you have the pixels for it — 600 DPI halves the print size the file asks for. It is worth it for fine line art and text scans, where the extra density is visible. For photographs, 300 DPI is the normal print standard.

Does this work on PNG files?

Yes. PNG stores density in a pHYs chunk, which Filesvo writes in pixels per metre as the format requires. Be aware that some older software ignores PNG density entirely and assumes 72 DPI.

Is my image uploaded to a server?

No. The file is read and rewritten by JavaScript running inside this page. It never leaves your device, so there is nothing for Filesvo to store or see.

Convert an Image to 300 DPI

To convert an image to 300 DPI, drop it into the tool below and choose 300. Filesvo rewrites the density tag inside the file and leaves every pixel exactly as it was, so the change is lossless and instant. If your image was rejected for being low resolution, read the section directly under the tool first — setting 300 DPI on its own will not fix that.

Set your image to 300 DPI

or drag and drop JPG/PNG files here — you can also paste from the clipboard

Processed on your device — files are never uploaded to Filesvo.

300 DPI on its own does not add any detail

DPI (dots per inch) is a note stored inside the file telling a printer how densely to lay the pixels down. It is a label on the pixels, not the pixels themselves. Changing it from 72 to 300 creates no new detail, sharpens nothing, and leaves the file the same size on disk.

What it does change is the physical size the image asks to be printed at. A 1200 × 1800 photo tagged 72 DPI asks for a 16.7 × 25 inch print, and looks soft because those pixels are stretched thin across it. The identical file tagged 300 DPI asks for 4 × 6 inches, and looks sharp. Same pixels, same bytes — a different instruction to the printer.

So the useful question is never 'is it 300 DPI'. It is 'does it have enough pixels for the size I am printing'. That is what the table below answers.

Pixels you need for a sharp 300 DPI print

Multiply the print size in inches by 300. If your image has at least this many pixels, tagging it 300 DPI will genuinely print sharply at that size. If it has fewer, no DPI value can rescue it — the detail is not in the file.

Print size	Pixels needed at 300 DPI
2 × 2 in — US passport photo	600 × 600
35 × 45 mm — most visa and ID photos	413 × 531
4 × 6 in — standard photo print	1200 × 1800
5 × 7 in	1500 × 2100
8 × 10 in	2400 × 3000
A6 — 105 × 148 mm	1240 × 1748
A5 — 148 × 210 mm	1748 × 2480
A4 — 210 × 297 mm	2480 × 3508
US Letter — 8.5 × 11 in	2550 × 3300

Millimetre sizes are converted at 25.4 mm to the inch and rounded to the nearest pixel.

How to check what your image can already print at

Divide each pixel dimension by 300 and you have the largest sharp print in inches. A 2400 × 3000 photo divides to 8 × 10 inches. A 1024 × 768 screenshot divides to about 3.4 × 2.6 inches — which is why screenshots almost never print well at document sizes, whatever their DPI tag says.

If you do not know your image's pixel dimensions, the image dimensions checker reads them without uploading the file. Once you know them, the table above tells you immediately whether 300 DPI is a formality or a genuine problem.

When the DPI tag matters, and when it is ignored

Printing: it matters. The tag is how the printer decides what physical size to render, unless you override the size in the print dialog.

Page layout software: it matters. Word, InDesign and similar place an image at the size its DPI tag implies, so a 72 DPI photo lands on the page more than four times too large.

Online submission portals: usually ignored. Most check pixel dimensions and file size, and never read the density tag at all. This is the single most common reason a photo that 'is 300 DPI' still gets rejected.

The web: ignored entirely. Browsers lay images out in CSS pixels and take no notice of the tag.

Passport, visa and ID photos

This is the most common reason people need 300 DPI, and it is worth separating the two requirements. A US passport photo is 2 × 2 inches, which is 600 × 600 pixels at 300 DPI. Most visa and national ID photos are 35 × 45 mm, which is 413 × 531 pixels.

If you are uploading to a government portal, it is almost certainly checking those pixel numbers and the file size — not the DPI tag at all.

If a portal rejects the photo for its dimensions, crop it to the right aspect ratio and resize it to the pixel count in the table — then set 300 DPI here. If instead the photo is being printed, or a form explicitly demands the file declare 300 DPI, the tag is all that needs fixing, and the tool above does that without touching the image.

Why this tool does not resample your image

Rewriting the tag and resampling the pixels are two different operations, and merging them into one button is how other converters end up quietly degrading files. Filesvo only rewrites the tag: JFIF density and the EXIF resolution tags for JPEG, the pHYs chunk for PNG. Your pixels come back bit-for-bit identical.

If you genuinely need more pixels, that is a resize, and it is worth being clear-eyed about it: enlarging an image invents detail that was never captured. It can help a little; it cannot recover what the camera did not record.

Frequently asked questions

Will converting to 300 DPI make my photo look better?: No. The pixels are untouched, so on screen the image is identical. It will print smaller and therefore sharper, because the same detail is packed into a smaller area — but no detail is added.
My form says '300 DPI minimum' but still rejects my file. Why?: Almost always because it is checking pixel dimensions, not the DPI tag. A 400 × 500 photo tagged 300 DPI is still a 400 × 500 photo. Compare your image against the table above for the size you need.
Does changing the DPI change the file size?: Only by a few bytes. The tag is a handful of numbers in the file header; no image data is re-encoded, so nothing is recompressed and nothing is lost.
Should I use 600 DPI instead?: Only if you have the pixels for it — 600 DPI halves the print size the file asks for. It is worth it for fine line art and text scans, where the extra density is visible. For photographs, 300 DPI is the normal print standard.
Does this work on PNG files?: Yes. PNG stores density in a pHYs chunk, which Filesvo writes in pixels per metre as the format requires. Be aware that some older software ignores PNG density entirely and assumes 72 DPI.
Is my image uploaded to a server?: No. The file is read and rewritten by JavaScript running inside this page. It never leaves your device, so there is nothing for Filesvo to store or see.

Change Image DPI

Set the DPI of JPG and PNG images to 72, 150, 300, 600 or any custom value — without re-encoding a single pixel.

Resize Image

Resize JPG, PNG and WebP images by percentage or to exact pixel dimensions — in your browser.

Image Dimensions Checker

Check the exact pixel dimensions, megapixels and aspect ratio of any image instantly — no upload.