The Best Free Online PDF Compressor
heyPDF's online PDF compressor reduces the size of any PDF file in seconds — no installation, no account, and no size limits on how many files you compress. Three adjustable compression levels give you full control over the balance between file size and output quality, from a gentle 30% reduction all the way to 90% size reduction for meeting strict upload limits.
Why Choose heyPDF to Compress PDFs?
- Up to 90% file size reduction on photo-heavy and scanned PDFs.
- Zero watermarks on the compressed output — ever.
- No daily limits — compress as many PDFs as you need.
- No sign-up — start compressing in seconds without an account.
- Works everywhere — any browser on Mac, Windows, Linux, iPhone, Android.
- Privacy-first — files auto-deleted after 2 hours, 256-bit SSL encryption.
Standard vs High vs Maximum Compression
heyPDF offers three presets to match different use cases:
- Standard (Recommended for most users): 20–40% size reduction. Images remain at 150 DPI — visually identical to the original on screen and for most printing. Safe for professional documents where appearance matters.
- High Compression: 50–70% reduction. Images at 96 DPI. Slight reduction in image zoom-quality, but text and charts remain perfectly clear. Great for email attachments and file sharing.
- Maximum Compression: 70–90% reduction. Most aggressive settings. Ideal when you must hit a specific limit (100KB, 200KB, 1MB) regardless of image quality. Text is always preserved at full clarity.
How PDF Compression Works
When you upload a PDF to heyPDF, our compression engine performs several operations simultaneously:
- Resamples embedded images to the target DPI for the selected compression level.
- Re-encodes images using optimized JPEG or JBIG2 compression algorithms.
- Subsets embedded fonts — retaining only the characters actually used in the document.
- Removes duplicate object references, unused resources, and redundant metadata.
- Repackages content streams into compressed object streams.
Text, fonts, tables, hyperlinks, and document structure are always preserved at full quality regardless of which compression level you choose.
Best Tools to Use Alongside PDF Compression
For maximum size reduction: first use Split PDF to remove unnecessary pages, then compress the remaining pages with Maximum compression. If your PDF contains scanned pages, run PDF OCR first to convert image-based text into real text — this allows for much more efficient compression.
How to use Compress PDF — step by step
Upload Your PDF
Drag your PDF onto heyPDF's Compress PDF tool, or click to browse. Google Drive and Dropbox import supported.
Pick Compression Level
Choose Standard for best quality, High for a smaller file, or Maximum to hit strict size targets like 100KB or 1MB.
Compress Online
Click 'Compress PDF'. Our servers process the file in seconds — typically 5–20 seconds for most PDFs.
Download the Result
The new file size is displayed before you download. Your compressed PDF is watermark-free and auto-deleted after 2 hours.
Why choose heyPDF?
100% Free Forever
No hidden charges, no credit card, no premium walls. All 26 tools are completely free.
No Registration
Use any tool instantly without creating an account or giving up your email.
Privacy First
All files are encrypted with 256-bit SSL and permanently deleted from our servers after 2 hours.
Works on Any Device
Desktop, tablet, iPhone, Android — any modern browser on any OS works perfectly.
Frequently Asked Questions
Typically 30–90% depending on content type and compression level. Scanned documents and photo-heavy PDFs compress the most. Text-only PDFs typically see 15–30% reduction as they're already efficient.
No. Text, fonts, and vector graphics are always preserved at full quality — they're lossless. Only raster images (photos, scans) are reduced in resolution. Even at Maximum compression, documents remain fully readable on screen.
Yes. Compressing PDFs on heyPDF is 100% free. No sign-up, no daily limit, no watermarks on the output, no subscription required.
heyPDF's Compress PDF tool processes one file at a time. For batch compression, compress each PDF in sequence — there are no daily limits, so you can compress as many files as needed.
The free plan supports files up to 25MB. The Pro plan supports up to 300MB. If your file exceeds the limit, use Split PDF to break it into smaller sections, compress each section, then re-merge.
Related PDF Tools
After using Compress PDF, you might also need these tools:
Related PDF Utilities
Expert Resources
How to Compress PDF Without Losing Quality — 5 Methods
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How to Make PDF Smaller — Reduce File Size Guide
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