PDF Compress
Reduce PDF file size by optimizing its structure
Drop a PDF here or click to browse
We'll optimize its structure to reduce file size
Compression works by rebuilding the PDF structure with object streams. Results vary depending on how the original was created. Already-optimized PDFs may not shrink further.
What compression can and cannot recover
Compression here means one thing: rewriting the PDF with object streams enabled and dropping unused references. The work is lossless, so every glyph, pixel, and vector path comes through untouched, and the savings depend on how the file was built rather than on a number you pick.
What the rebuild does
The tool rewrites the document with object stream compression and clears unused metadata while keeping the title, author, subject, and keywords intact. Files exported from a word processor tend to shrink 10 to 30 percent. It never re-encodes your images or runs OCR, so nothing about the rendered page changes.
Where the savings hide, or do not
The result tracks what the source already did to itself:
- A PDF saved by Acrobat, Preview, or a recent Word often ships with object streams already on, so there is no headroom and the tool reports it as already optimized.
- A PDF from an older exporter or a web generator carries loose structure, where 15 to 40 percent savings are common.
- A scan-heavy PDF stays about the same size, for the reason in the note above.
The result panel shows the original and rebuilt sizes side by side before you download, so you can judge whether the rebuild earned its keep.
Two questions worth answering
- Can I set a target file size?
- Not in this version. The compression is structural and lossless, so the outcome depends on the file rather than a target. A target-size mode would need lossy image re-encoding, which is on the roadmap.
- Why does my compressed PDF look identical?
- Because it is identical to look at. The rebuild changes the file layout, not the rendered content. Smaller on disk and the same on screen means it worked.