🖨️ Change Image DPI (300 DPI Converter)
Set your PNG or JPEG to 300 DPI (or any value) for printing — this edits the DPI metadata only, so the image quality is never changed.
DPI (dots per inch) tells a printer how large to print an image; it doesn’t change the pixels or the file’s appearance on screen. This edits the density metadata directly — PNG’s pHYs chunk or JPEG’s JFIF header — without re-encoding, so quality is untouched (unlike “resize to 300 DPI” tools that resample). For a specific print size you also need enough pixels: a 4×6" photo at 300 DPI needs 1200×1800 pixels. 🔒 Runs entirely in your browser — the image is never uploaded.
How the change image dpi (300 dpi converter) works
DPI (dots per inch) is a metadata tag that tells a printer how large to render an image; it has no effect on how the file looks on screen. This tool reads and rewrites that tag directly in the file — the pHYs chunk in a PNG or the JFIF density fields in a JPEG — without re-encoding the image, so not a single pixel changes. Drop in a PNG or JPEG, see its current DPI, pick a preset (72, 96, 150, 200, 300, 600) or type any value, and download the copy.
This solves a specific, maddening problem: a print shop, print-on-demand service or exam/visa portal demands “300 DPI”, but your image is tagged 72. Crucially, most tools labelled “convert to 300 DPI” actually *resample* the image (adding or dropping pixels, softening it) — that’s the wrong fix when the requirement is really about the metadata tag. This one changes only the tag, losslessly. The catch to understand: DPI plus pixel dimensions together determine the physical print size. 300 DPI on a 300×300-pixel image prints at just 1×1 inch; to print a 4×6" photo at 300 DPI you need 1200×1800 pixels. Setting the tag doesn’t add detail that isn’t there. Everything runs in your browser.
Frequently asked questions
How do I change an image to 300 DPI?
Open your PNG or JPEG, click the 300 preset (or type a value), and download. The tool writes 300 into the file’s density metadata without touching the pixels, so quality is unchanged.
Does changing DPI reduce image quality?
No — this edits only the metadata tag, with no resampling or re-encoding, so the image is byte-for-byte identical except for the DPI value. That’s different from “resize to 300 DPI” tools, which resample and can soften the image.
Does higher DPI make my image look better on screen?
No. On screen an image is shown by its pixels; DPI is ignored. DPI only matters for printing, where it sets how large those pixels are placed on paper.
Why does my 300 DPI image still print small (or blurry)?
Because print size = pixels ÷ DPI. If the image doesn’t have enough pixels, 300 DPI prints small; stretching it larger is what looks blurry. For a 4×6-inch print at 300 DPI you need 1200×1800 pixels — setting the tag can’t add detail that isn’t in the pixels.
Is my image uploaded?
No — the DPI is changed entirely in your browser by editing the file’s bytes, so the image never leaves your device.