Compress PDF to a target size: understand the limits
A PDF compressor can reduce file size, but an exact target such as 100 KB is not always achievable without changing image quality or removing content.
Updated September 28, 2026 · FreePDF Tools
Why PDFs shrink differently
A text-heavy PDF may contain little redundant structure, while an image-heavy scan can be dominated by JPEG or other already-compressed images. Lossless recompression cannot remove information from those images.
When lossy optimization is needed
If a submission system requires a hard file-size limit, you may need image resampling or quality reduction. That is a different tradeoff from lossless compression because visual quality can change.
Check the result
Open the compressed PDF, compare text and images, and confirm that forms, links and page count remain correct before replacing the original.
Use the right workflow
Start with the lossless browser-local compressor. If the target is still not reached, decide explicitly which visual quality or page content can safely be changed.