Change Image DPI
Set the DPI of a JPG or PNG for print prep — 72, 150, 300, 600, or any custom value. Pure metadata edit — pixels untouched. Runs in your browser.
Drop a JPG or PNG to change its DPI
Metadata-only edit · pixels untouched · never uploaded
How DPI editing works
DPI is stored as metadata, not as pixel data. In JPG, the density lives in the JFIF (APP0) marker; in PNG, it lives in the pHYs chunk. ToolChop parses these containers, rewrites the density tag to your chosen DPI, and emits a new file that is byte-for-byte identical to the original except for those few bytes. No re-compression, no quality loss — the safest possible edit on an image file.
Why a local DPI editor matters
DPI changes happen in print workflows: photographers preparing prints, designers preparing book/album covers, agencies submitting to print presses, authors prepping interior figures. The files are usually pre-publication, NDA-protected, or personal. Uploading them to a random web tool to flip a metadata flag is a needless data path. ToolChop keeps everything local.
Common DPI targets
- 72 DPI — web / screen (Apple default)
- 96 DPI — web / screen (Windows default)
- 150 DPI — newspaper print, large-format proofs
- 200 DPI — magazine print, brochures
- 300 DPI — book interiors, photo prints, fine-art (the most common "press-quality" target)
- 600 DPI — high-detail line art, technical illustrations
Frequently asked questions
How do I change the DPI of an image online for free?
Drop your JPG or PNG, pick the target DPI from a preset (72, 96, 150, 200, 300, 600) or slide to any value from 36 to 1200, and click Download. The change is metadata-only — your pixels are not touched. No account, no upload, no daily limit.
Does ToolChop upload my image?
No. The image is parsed and the DPI metadata is rewritten in your browser. Your file never leaves your device — important when the image is a confidential design proof, a photographer's print, or a book cover going to a press upload.
Why is the privacy story important for a DPI tool?
DPI changes happen in print workflows: photographers preparing prints, designers preparing book/album covers, agencies submitting to print presses. Those files are often pre-publication, NDA-protected, or personal. Uploading them to a random web tool just to flip a metadata flag is a needless data path. ToolChop keeps everything local.
Does changing DPI resample or change pixel dimensions?
No. DPI is purely a metadata hint that tells print software 'render these pixels at this density'. The pixel data is identical. A 3000 × 3000 image at 72 DPI prints at ~41 inches; the same image at 300 DPI prints at 10 inches — same pixels, different physical size. If you also need to change pixel dimensions, use the Image Resizer first.
Is the output file size the same?
Yes, almost exactly — the change is a handful of bytes in the JFIF marker (JPG) or the pHYs chunk (PNG). The compressed pixel data is untouched, so the file is bit-for-bit identical except for the density tag.
What is DPI vs PPI?
DPI (dots per inch) is a print-press term — the number of ink dots a printer puts down per inch. PPI (pixels per inch) is a screen term — the number of pixels per inch a display shows. In digital image metadata, the two are used interchangeably; the JFIF and PNG standards both call it 'density'. ToolChop uses 'DPI' for familiarity since that's what most print workflows ask for.
Why do printers ask for 300 DPI?
300 DPI is the rough threshold for 'photographic quality' at normal viewing distance. Above 300, the eye can no longer distinguish individual dots. Most commercial printers (book interiors, magazine ads, fine-art prints) specify 300 DPI as the minimum. Billboards and other large-format prints often accept 150 or even 72 DPI because viewing distance is much larger.
Can I change DPI for a WebP, HEIC, or AVIF?
Not on this page — ToolChop's DPI tool only handles the JPG (JFIF) and PNG (pHYs) DPI metadata containers. WebP and AVIF don't have a standard DPI field; HEIC stores it in EXIF but rewriting EXIF is a separate workflow. For those formats, convert to JPG or PNG first (we have converters), then set the DPI here.
What does it mean when my image shows 'DPI: not set'?
JFIF allows 'units = 0' (no DPI specified) and PNG allows omitting the pHYs chunk entirely. When that happens, print software falls back to its own default — usually 72 or 96 DPI. Setting an explicit DPI removes that ambiguity, which is why press uploads usually require an explicit value.
Will the new DPI show up in Photoshop, GIMP, and Lightroom?
Yes. ToolChop writes standards-compliant DPI metadata (JFIF density for JPG, pHYs chunk for PNG). All major image editors and print drivers read those fields. Confirm with File → Image Size in Photoshop or Image → Image Properties in GIMP.
Is the conversion lossless?
Yes — completely. The pixel data, color profile, EXIF tags, and other metadata are all preserved bit-for-bit. Only the density field is changed. This is the safest possible operation on an image file.
Why use ToolChop instead of Photoshop, GIMP, or an online DPI tool that uploads my file?
Photoshop and GIMP work but require an install and an open file. Online DPI tools that upload the file are a needless data path for what is a 4-byte metadata edit. ToolChop does the edit in your browser in milliseconds — no install, no account, no upload, no re-encoding.