Shrink PDF

Shrink PDF makes a PDF smaller by rendering every page to pixels, re-encoding them as JPEG or PNG at a resolution and quality you choose, and placing each one back on a fresh page of exactly the original size. That is the whole mechanism and also the whole catch: the result is a stack of photographs of the pages, so selectable text, search, copy and paste, screen reader output, links, form fields and bookmarks are gone from it. The projected file size shown before you commit is measured from one page actually re-encoded at your settings, then scaled by the area of the other pages.

How it works

  1. Drop a PDF Drop one PDF onto the page. Its pages are listed and the totals panel shows what the file weighs now.
  2. Set the resolution Drag the resolution slider between 72 and 300 DPI; 150 is the default. The hint says how many pixels an A4 page comes to at that setting.
  3. Choose the image format and quality JPEG is the default and the right choice for scans; PNG is lossless and suits flat line art and screenshots. The quality slider applies to JPEG — below about 0.60 the edges of small text start to smear.
  4. Try greyscale, and drop pages you do not need Greyscale takes a long way off a scan of black text on white paper. The page range box keeps only the pages you name, so 1-3, 7, 9- also trims the document.
  5. Watch the projection, then shrink and download Compare the original and projected figures, press shrink PDF, and download the result. It runs one page at a time and can be stopped part way; the PDF then holds the pages that finished.

Questions

Will the text still be selectable afterwards?
No. Every page is rendered to an image and embedded as one, so selectable text, search, copy and paste, anything a screen reader could announce, and links, form fields and bookmarks are all gone from the result. Keep the original file — this tool produces a smaller companion, not a replacement.
Why is my shrunk PDF bigger than the one I started with?
Because the source was probably already images, or already efficiently compressed, so redrawing it gains nothing. The tool detects this and says so. A lower resolution, JPEG rather than PNG, or greyscale will each bring the size down; PNG in particular can come out several times larger than the original on photographs or a colour scan.
Can it output WebP, which would be smaller still?
No, and the control says why: a PDF can carry JPEG and PNG images and nothing else, so WebP is listed but disabled however small it would be. The WebP option stays visible rather than hidden so the question gets an answer.
How reliable is the projected size?
It is measured rather than guessed. One page is really rendered and encoded at your current settings, then every other page you are keeping is scaled by its area against that one, plus a small allowance per page and per document. The real file lands near the figure, not exactly on it.

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