ScoutMyTool

Compress PDF

Reduce a PDF’s file size to email or upload it. Choose a lossless squeeze that keeps everything identical, or re-encode the images for a much smaller file.

By the ScoutMyTool team · Last reviewed 14 November 2026 · How we build our tools

How can I reduce the size of a PDF?

Choose your PDF and a quality level, then select Compress PDF. High is lossless and runs in your browser (typically 10–40% smaller); Medium re-encodes images at 150 dpi and Low at 72 dpi on our server, which saves the most on scanned or photo-heavy files. Server files are deleted as soon as the result is sent back.

or drag and drop it here

Processed on our server over an encrypted connection, then deleted as soon as the result is sent back.

More options

Image-only mode runs entirely in your browser (nothing uploaded). The quality preset above sets the JPEG quality (High≈85%, Medium≈60%, Low≈40%). Only JPEG images are re-encoded; vector text, fonts, and line art stay pixel-perfect.

For each embedded image, encodes both a JPEG and a lossless PNG-style (Flate) version and keeps the smaller — flat-colour charts/line-art shrink more as lossless, photos as JPEG. Image-only mode; runs in your browser.

Linearizes the PDF (Ghostscript -dFastWebView) so a browser can render the first page before the whole file arrives — useful for large PDFs served on the web. Applies to the Medium / Low / Subset-fonts (server) presets; the in-browser High and Image-only modes are unaffected.

For users on slow connections: forces the High lossless client-side path regardless of the quality preset above. Nothing is uploaded. Skips font subsetting and image re-encoding — savings are smaller (10-40%) but completion is near-instant after the file finishes loading in the browser.

When > 0, overrides the quality preset above. Iteratively re-encodes JPEG images at progressively lower quality (85 → 70 → 55 → 40 → 25 → 10) until the output PDF is at or below this target. Image-only client-side path — text/fonts stay pixel-perfect. Leave 0 to disable. If the target is unreachable (text-heavy PDF with no images), the smallest achievable size is returned with a note.

Comma-separated page numbers / ranges (same syntax as Split PDF) that should be left UNTOUCHED — useful for signature pages, completed forms, or graphics-heavy pages where compression would damage detail. The rest of the document is compressed normally; flagged pages are copied byte-for-byte from the original.

How to use Compress PDF

  1. Choose or drop your PDF.
  2. Pick a quality level.
  3. Select Compress PDF and download the smaller file.

Which level to choose

High is lossless: it recompresses the file’s internal data and removes duplicates without touching image quality. It helps most on documents produced by office software.

Medium re-encodes images at 150 dpi — sharp on screen and fine for most printing. Low uses 72 dpi for the smallest file, which suits screen viewing and email. Scans and photo-heavy PDFs shrink the most, because nearly all of their size is images; a text-only PDF is already small and changes little.

More options include web, print and archive profiles, a target file size, and leaving chosen pages (for example signed pages) untouched.

Where your file goes

High runs entirely in your browser. The other levels need image tools that run on our server: the file is sent over an encrypted connection, processed in a temporary folder and deleted when the request ends. Files up to 50 MB are accepted.

Frequently asked questions

How much smaller will my PDF be?

It depends on what is inside. Lossless compression typically saves 10–40%; re-encoding images can cut a scanned document by well over half. Text-only files change little because they are already small.

Will the text still be sharp?

Yes. Compression re-encodes images; text and vector graphics stay sharp at every level.

Is my file kept on your server?

No. Server compression works in a temporary folder that is deleted as soon as the result is sent back, and we never look at the contents.

Is there a size limit?

Files up to 50 MB can be compressed on our server. Lossless (High) compression in your browser has no fixed limit.

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