Reduce PDF File Size Without Losing Quality
FreeMake your PDF smaller for email attachments, uploads, and sharing. Targets the actual cause of large file size. Free, browser-based, no upload.
What's next
Settings guide
Diagnosing your PDF before compressing:
Open your PDF in any reader and check file properties (usually under File > Properties or Document Properties). The "Producer" field tells you how it was created:
- ·"Acrobat Distiller" or "Adobe PDF" — Professional origin; likely already somewhat optimised
- ·"Microsoft Word" — Usually contains unsubsetted fonts and conversion overhead; compresses well
- ·"Xerox" / "Canon" / "HP" — Scanner origin; images dominate; compress aggressively
- ·"LibreOffice" / "OpenOffice" — Usually efficient; compression gains will be modest
Size reduction targets by PDF type:
- ·Email-attachment limit (5MB) — Use Ebook mode; achieves 60-80% reduction on scanner PDFs
- ·LMS or form upload limit (2MB) — Use Screen mode; recompresses images to 72 dpi
- ·Large archive or book — Use Prepress mode; preserves quality while removing metadata
Format comparison
PDF compression vs converting to image: Converting every page to an image (JPEG or PNG) then back to PDF creates a flat, unsearchable document. This is sometimes smaller but destroys text content — making copy-paste, search, and accessibility impossible. Always prefer proper PDF compression over image flattening unless the document is already image-only.
PDF vs ZIP for sharing: A PDF compressed with proper image reduction is almost always smaller than a ZIP of the same PDF. ZIP compresses streams well but cannot recompress embedded images — the PDF compressor can.
Browser-based vs desktop software: Adobe Acrobat Pro and Ghostscript can produce marginally better compression for very large files. This tool is significantly better than most online alternatives because it processes locally — no upload delays, no file size limits from server restrictions.
How it works
Upload
Drop your large PDF into the tool — any page count, any source.
Select quality
Choose Screen for maximum reduction, Ebook for balanced quality, or Print to preserve print quality.
Process
The tool recompresses images, subsets fonts, and strips unnecessary metadata in your browser.
Download
Save the smaller PDF. The result panel shows original vs compressed size.
About this format
A PDF can be large for completely different reasons, and the most effective way to reduce its size depends on diagnosing the cause first.
The four most common causes of oversized PDFs: scanner images embedded at 600 dpi when 150 dpi is sufficient for screen viewing; fonts embedded in full when only a subset of characters are actually used; unflattened transparency layers from design software like Illustrator or InDesign; and conversion artifacts from Word or PowerPoint (converted documents sometimes duplicate objects or embed unnecessarily large resources).
Each cause has a different fix. Scanner PDFs compress dramatically with image quality reduction. Oversized fonts compress through subsetting. Transparency and conversion issues respond to content stream re-encoding. This tool identifies the dominant factor and applies the appropriate compression — you do not need to know which applies to your file. Just upload, select your quality level, and compare the before and after.