Gmail/Outlook delivery
Keep combined attachments below provider limits without splitting emails.
Compress PDF Online
Reduce PDF file size without losing quality, right in your browser.
Processed in your browser. Nothing uploaded.
Drop a PDF here or click to browse
Single PDF file
All processing happens in your browser. No files are uploaded.
What Is PDF Compression?
Compress PDF is a free online tool that reduce PDF file size without losing quality, right in your browser. No files are uploaded — everything is processed locally on your device.
PDF compression reduces file size by 40–80% for image-heavy documents and 10–30% for text-heavy documents, without degrading the readability of text, fonts, or vector graphics. The compressor re-encodes embedded images at a lower quality level, strips redundant metadata, and streamlines the internal object structure defined in the PDF specification (ISO 32000). Text streams and vector paths pass through untouched — which is why compressed PDFs remain fully searchable and selectable. This browser-based PDF compressor is essential when you need to email documents under attachment limits (Gmail allows 25 MB, Outlook 20 MB), upload to government portals with strict size caps, or free up disk storage. Image-heavy PDFs like scanned contracts, presentation decks, and design portfolios see the largest reductions because raster images dominate their file size. The entire process runs locally in your browser via pdf-lib and PDF.js — so sensitive contracts, tax filings, and medical records are never transmitted to an external server. This is a structural privacy guarantee, not a policy promise.
Privacy guarantee: Compress PDF processes all files directly in your browser using WebAssembly. No data is uploaded to any server, no information is collected, and the tool works offline after loading. Unlimited usage with no signup, no watermarks, and no file size limits.
How to Use Compress PDF
Upload your PDF
Select a PDF file from your device or drag it into the upload area. Files of any size are accepted.
Choose compression level
Pick a preset: balanced (good size reduction with minimal quality loss), maximum compression, or best quality (smallest reduction, sharpest images).
Compress and download
Click Compress to shrink your PDF. Review the before-and-after file size, then download the optimized file.
Why Use Our PDF Compressor?
Processes locally via WebAssembly — your document never leaves your device
Three compression presets: balanced, maximum reduction, and best quality
See exact file size savings before you download
Text stays searchable and copy-pasteable after compression
Handles large multi-page PDFs (100+ pages) without slowdown
Output is free of watermarks, branding, or injected metadata
Unlimited compressions with no daily caps or signup
Advanced Guide: Compress PDF
PDF Compression Benchmarks (Observed Ranges)
Compression gains depend on embedded image density. Text-heavy PDFs are already compact and show smaller reductions than scanned or slide-deck documents.
- Text-heavy reports: 10-30% smaller — Mostly metadata and structure optimization
- Scanned documents: 45-80% smaller — Image re-encoding drives most savings
- Slide decks exported as PDF: 30-65% smaller — Large hero images compress well
| Target Use | Best Choice | Why |
|---|---|---|
| Email attachments under strict cap | Maximum compression | Prioritizes smallest final file size |
| Client review and readability | Balanced | Strong size reduction with minimal visible loss |
| Print-focused delivery | Best quality | Preserves image fidelity for print workflows |
High-Intent Use Cases
Government portal upload
Meet strict file size caps on forms and compliance submissions.
Faster mobile access
Reduce download time for recipients on slower or metered connections.
Frequently Asked Questions
How much can I reduce my PDF file size?
Image-heavy PDFs (presentations, scanned documents, brochures) typically shrink by 40-80%. Text-only documents like research papers see 10-30% reductions because the text is already compact. The preview shows exact savings before you download.
Does compression affect the text quality in my PDF?
No. Text, vector graphics, and fonts remain sharp at every compression level. The compressor targets embedded raster images and redundant internal metadata — never the text layer.
Can I compress a PDF to under a specific size like 1 MB or 2 MB?
Select the maximum compression preset for the smallest output. If the result is still above your target, try compressing a second time. Results depend on the original content — a 50 MB image-heavy PDF can often reach under 5 MB, but a 3 MB text-only file has less room to shrink.
Can I compress password-protected PDFs?
Yes. Enter the password when prompted so the tool can read the file. The compressed output retains the same protection unless you choose to remove it.
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