Guide ·
Why won't my PDF compress any further?
Compress PDF makes most photo-heavy PDFs much smaller, but sometimes the new size is barely different, or even a little bigger. That usually tells you something about what's inside the file.
Step by step
- 01
Try Strong
Strong brings large photos down to 96 DPI, the smallest setting. Light doesn't change images at all.
- 02
Compare the sizes
The new size is shown before you download. If it isn't smaller, keep your original.
- 03
Work through the reasons below
Each one has a different fix.
It's mostly text
Text and vector drawings take very little space and are never turned into pictures, so a text-only PDF is already small and has little to lose.
The images are already small
Images are only resampled when they hold more detail than the page needs: more than about 150 DPI across the page at Balanced, or 96 DPI at Strong. Images below that are left alone, and a resampled image is used only if it comes out smaller.
It's a black-and-white scan
Scans saved in pure black and white are already very compact, and compression leaves them as they are. The same goes for images in CMYK colour, which are common in print-ready files.
It has been compressed before
A file that has already been through a compressor has little left to remove. Compressing it again mostly repacks the same data, and can even come out slightly larger.
The size is in fonts or drawings
Embedded fonts and complex vector drawings, such as detailed maps or charts, are kept as they are apart from removing duplicates.
Still too big?
- Remove pages you don't need with Delete pages.
- If you can send several files, cut it into parts with Split PDF.
- For a PDF made from photos, shrink the photos with Compress image and rebuild the PDF with JPG to PDF.
There's no setting for an exact size such as 200 KB. See how to reduce PDF file size for choosing a level.
Questions
- Why is the compressed file bigger than the original?
- Rewriting a file that was already compact can come out slightly larger. Keep the original in that case.
- Will Strong make my document blurry?
- Text and drawings stay sharp. Photos lose detail, which shows mostly when they're printed or zoomed in.