PDF Tools
Compress PDF
Shrinks a PDF for email or upload limits. Works best on scanned or image-heavy PDFs.
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Files are processed on your device. Nothing is uploaded to a server.
Compress PDF: what this tool does
Reduce the size of a PDF for email, uploads, sharing, or storage. Image-heavy and scanned PDFs often benefit most because their page images can dominate the file size.
How it works
- 01
Set a target size in MB and upload your PDF — scanned, image-heavy PDFs benefit the most from compression.
- 02
We try a lossless pass first, then progressively re-encode pages as images only if that alone isn't enough to hit your target.
- 03
Download the result — we'll tell you honestly if the target wasn't reachable without making the document illegible.
When this tool is useful
- Getting a PDF under an upload or email limit.
- Making a scanned document easier to share.
- Reducing storage usage without manually rebuilding the document.
Supported formats
What to know before you use this tool
PDF compression is mainly useful when a document is too large for an email, upload portal, or storage workflow. The amount of reduction depends heavily on whether the PDF contains scanned images or mostly vector text.
Good use cases
- Email attachment limits
- Online application upload limits
- Reducing image-heavy or scanned PDFs
A sensible workflow
- Check the actual size limit first.
- Try the least aggressive compression that can meet it.
- Inspect small text, signatures, and diagrams in the final PDF before submitting it.
Things worth checking
- Text-only PDFs may not shrink much because they are already compact.
- Strong image compression can reduce sharpness and may remove selectable text if pages are flattened.
- Keep the original so you can try a different target later.
Continue learning
Tips for better results
- Use the least aggressive compression that meets your target.
- Inspect small text after compression when the source contains scans.
- If the PDF is mostly vector text, compression may produce a smaller improvement than it does for image-heavy scans.
What to expect
Strong compression can reduce image sharpness. A PDF made from high-resolution scans may need image re-encoding to achieve a large size reduction.
Frequently asked questions
Will this affect text quality?
If a page still exceeds the target after a lossless pass, that page is re-rendered as a flattened image — this shrinks file size a lot, but text on that page is no longer selectable/searchable.
Can I compress a password-protected PDF?
The password needs to be removed first — a locked PDF can't be read and re-encoded until it's unlocked.
Why didn't compression change the file size much?
Text-only PDFs (not scanned images) are usually already small and don't have much to compress — heavy compression gains mostly come from scanned pages or embedded high-resolution photos.
Common mistakes to avoid
Targeting the exact size limit instead of comfortably under it
Compressing to precisely 25MB for a 25MB email limit leaves zero margin — attachment overhead and encoding can push it slightly over. Target a bit under the actual limit.
Not distinguishing text-heavy PDFs from scan-heavy ones
A PDF made of scanned pages is really a set of embedded photographs and compresses very differently from a PDF built from typed text. Scanned documents usually need more aggressive compression to hit the same target size.
Compressing a document that already has small embedded images
If a PDF is already small and text-dominant, aggressive compression settings won't reduce it much further and can start affecting text sharpness for little size benefit. Check the current size before deciding how hard to compress.