filehugger.comHow to choose DPI when converting a PDF to images
DPI decides how many pixels each PDF page becomes. Pick too low and small print fuzzes out; pick too high and a lunch-size document turns into a data plan problem. We measured the real cost with this site's own renderer.
The measured reality
One 16-page, 60 KB text PDF became 2.5 MB of JPEGs at 72 DPI, 6.8 MB at 150, and 18.4 MB at 300. Every DPI step costs roughly 2.7× the bytes. Rasterizing is inherently expensive — the first question is always whether you need images at all.
Pick by destination
- 72 DPI — thumbnails and previews only. Body text is readable, fine print is not. Use when the images are small on screen anyway.
- 150 DPI — the screen sweet spot. Sharp for slides, web pages, chat attachments and on-screen review; a fraction of the print-grade weight. This is the tool's default for a reason.
- 300 DPI — print and archives. The standard when paper or small-print legibility is the goal. Expect the multi-megabyte bill our measurement shows.
Two honest warnings
- Images lose the text. Rendered pages contain no selectable, searchable text. If someone needs to copy from it, they'll need OCR to undo what you just did — send the PDF instead.
- Don't rasterize to "compress". As the numbers above show, images of a PDF are typically far larger than the PDF. To shrink a PDF, use Compress PDF, not an image round-trip.
Doing it
Open PDF to JPG (or PDF to PNG for lossless pages), drop the file, pick the resolution — or choose a goal and hit Apply recommended settings, which maps exactly to the table above — and convert. The scorecard on the download page shows what the choice cost in bytes.
Tools used in this guide
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