Compress PDF
Re-encodes large embedded images as JPEG at one of three levels. Text and vector graphics are copied unchanged, and if the result isn’t smaller you get the original back.
What Compress PDF does
Compress PDF makes a file smaller by re-encoding the photos and scans embedded in it as JPEG images, at the size and quality you choose. Text, fonts and vector graphics are copied unchanged, so they stay as sharp as in the original.
If the compressed file isn't smaller than the original, you get the original back instead of a bigger file.
How to compress a PDF
- Drop one or more PDFs on the box above, or click it to choose files.
- Pick a compression level: Light, Recommended or Strong. Turn on Convert images to grayscale if the document doesn't need color.
- Select Compress. The before and after sizes are shown. Download each file, or use Download all to get one ZIP.
Compression levels
| Light | Images longer than 2,600 px are scaled down, then saved as JPEG at 82% quality. |
|---|---|
| Recommended (default) | Images capped at 1,800 px, JPEG at 68% quality. |
| Strong | Images capped at 1,200 px, JPEG at 50% quality. |
| Convert images to grayscale | Re-encoded images are saved in shades of gray. Text and drawings keep their color. |
Limits
- Images under 12 KB, transparency masks and images that aren't 8-bit RGB or grayscale (CMYK, for example) are left as they are.
- A re-encoded image replaces the original only if it's at least 8% smaller.
- PDFs that are mostly text are already compact, so expect little change.
- There's no target-size mode yet, such as "under 100 KB".
- Any change to a file breaks a certificate-based digital signature in it.
Where your file goes
Compression runs in this browser tab with pdf-lib and your browser's built-in JPEG encoder. Your PDF isn't uploaded; the smaller copy is made in the tab and goes to your downloads.
If you're signed in, the result panel also offers Save to My documents. Only that button uploads the file, to your account's storage.
Questions
Will compression make my text blurry?
No. Only embedded images are re-encoded. Text, fonts and vector drawings are copied unchanged, so text stays as sharp as it was.
Why didn't my PDF get smaller?
Most of its size isn't in images the tool can re-encode. Text-only PDFs are already compact, and small images, CMYK images and transparency masks are skipped. When the output isn't smaller, you get the original file back.
How do I get the smallest file?
Choose Strong and turn on Convert images to grayscale. Strong caps images at 1,200 px on the longest side at JPEG quality 50%, which suits reading on screen. Check the result before you send it.
Is there a file size or daily limit?
There's no daily limit and no file count limit in the tool. Files are processed in your browser, so the practical limit for very large PDFs is your device's memory.
Are links, bookmarks and form fields kept?
Yes. The tool replaces image data inside the file and saves everything else as it was, including links, bookmarks and form fields.
What happens to a password-protected PDF?
You're asked for the password when you add the file. The compressed copy has no password, so run Protect PDF on it if it needs one.