Reduce a scan archive
Shrink large scanned PDFs for long-term storage or email attachment limits while keeping text legible.
- Upload the scanned PDF
- Select a quality level
- Compress and compare the size reduction
- Download the compressed document
PDF Tools
PDF Compress
Repack your PDF's object structure in the browser to trim file size. Images, text, and streams are left untouched and quality is fully preserved. Processed locally with no uploads.
PDF tools
PDF Compress
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OUTPUT
PDF Compress
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In brief
Repack your PDF's object structure in the browser to trim file size. Images, text, and streams are left untouched and quality is fully preserved. Processed locally with no uploads.
Reviewed: 2026-09-18
What this tool supports
- Repack your PDF's object structure in the browser to trim file size. Images, text, and streams are left untouched and quality is fully preserved. Processed locally with no uploads.
- All processing runs locally in your browser
- No data uploaded, stored, or transmitted
- Works offline after initial page load
- Instant results with download support
How to use PDF Compress
Reduce PDF file size entirely in your browser. Choose compression level for the best balance of size and quality. No uploads required.
Step 1
Upload your PDF
Drag and drop or click to upload. The tool accepts standard PDF files of any size.
Step 2
Choose compression level
Choose Strong, Recommended, or Basic, then click Compress. The tool reports the actual size before and after.
Step 3
Compress the PDF
Click Compress to process the file. The browser optimizes the PDF structure locally.
Step 4
Download the compressed PDF
Save the smaller PDF to your device. Compare the file sizes to see the reduction.
Common mistakes
Compressing already-compressed PDFs expecting significant reduction
Consequence: Double compression gives little or no further reduction; image quality is never affected.
Fix: Check the original file size first. Heavily compressed PDFs won't benefit much from re-compression.
Expecting the compression level to change print quality
Consequence: The presets only change internal object packing — they cannot blur text or resample images.
Fix: Print output is unaffected by the preset — choose whichever level gives you the file size you need.
Expecting compression to fix corrupted PDFs
Consequence: Compression works on valid PDF structures; corrupted files may fail or produce worse output.
Fix: Validate the PDF first. Use a repair tool for corrupted files before compressing.
Expecting text-only PDFs to compress significantly
Consequence: PDFs with mostly text have little redundant data to compress.
Fix: Text-only PDFs usually shrink little or not at all; the tool always reports the real before/after size.
Compressing already-optimized PDFs
Consequence: Re-compressing a PDF that is already optimized may not reduce size further.
Fix: Check the original file size before compressing to set realistic expectations.
Best practices
- Strong and Recommended produce identical output; Basic disables object streams and can make the file slightly larger.
- Test one representative file first to see how much repacking saves.
- Repacking works on object structure rather than content, so image-heavy and text-only files usually gain about the same.
- Keep the original file until the compressed output is verified at the intended display or print size.
Connected workflows
Prepare a document for upload limits
Compress a PDF to fit a portal’s maximum file-size requirement, checking readability of the smallest pages afterwards.
- Upload the source PDF
- Choose the quality level matching the size limit
- Compress and verify readability
- Download the result
Browser limitations
- Very large files may be slow to process
- Browser memory limits apply to very large images; files of several hundred megabytes are processed in a Web Worker with graceful degradation
Authoritative resources
Concrete examples
- Input
- Sample input
- Result
- Result
Example usage.
Frequently asked questions
How does PDF compression work?
The tool repacks your PDF's object structure in the browser. Embedded images and content streams are not re-encoded.
How much can compression reduce file size?
Reduction depends on the file. Repacking usually saves a single-digit percentage and can occasionally make a file slightly larger — the tool always shows the real before/after size.
Does compression reduce visual quality?
The tool offers three repacking presets — Strong, Recommended, and Basic. All keep image and text quality identical; only the internal object packing differs, so size changes are usually modest.
Is my PDF uploaded to a server?
No. All compression happens locally in your browser. Your PDF data never leaves your device.
Can I compress encrypted PDFs?
Yes — enter the PDF's password and the tool decrypts and compresses it locally.
How much can PDF compression reduce file size?
Reduction depends on the file. Repacking usually saves a single-digit percentage and can occasionally make a file slightly larger — the tool always shows the real before/after size.
Does compression affect PDF quality?
All three levels preserve quality — images are never re-encoded.
Can I compress password-protected PDFs?
You need to enter the correct password before compression.
Privacy and offline behavior
PDF Compress re-encodes the uploaded document inside this browser tab and writes the compressed file locally. Page content and metadata never leave the device; files are used only on explicit user action, and the page continues to work offline after the initial load.