Compress PDF
Reduce PDF file size while maintaining quality
Updated · Guide: How to Compress PDF Files for Email
Processed on our server. Sent over HTTPS to an isolated job, then deleted once you download.
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How to use Compress PDF
Upload your PDF
Click the upload area or drag and drop your PDF. Files up to 50 MB are supported.
Choose a compression level
Pick Less Compression (lossless cleanup), Recommended (images re-encoded at JPEG quality 75), or Extreme Compression (JPEG quality 50, images capped at 1200 pixels).
Click Compress PDF
Your file is sent to the server, processed with MuPDF, and the result is sent back to your browser.
Download the compressed PDF
Review the file size reduction shown, then download your compressed PDF.
What is PDF compression?
Shrink your PDF file size for email, uploads, or archiving. Choose a lossless cleanup or one of two image-recompression levels. Processing runs on our server with MuPDF, and text, vector graphics, and fonts are never re-encoded.
PDF compression makes a PDF file smaller, mostly by shrinking the photos and scans embedded in it. How small it can get depends on what is inside: in most oversized PDFs the weight sits in embedded photos and scans, not in text, so Compress PDF works on the images: it re-encodes them as JPEG and caps their pixel dimensions, while text, vector graphics, fonts, and page layout pass through untouched. Every level also rebuilds the file structure, dropping unused objects and merging duplicates.
The work runs on our server using MuPDF rather than in your browser tab. See our processing model for details on transport security and file-retention policy.
The limits that force compression are rarely negotiable. Gmail and Yahoo cap attachments at 25 MB and Outlook.com at 20 MB; many government portals, university submission systems, and job application forms set the ceiling as low as 5 or 10 MB. Getting a 30 MB scan-heavy report down to 8 MB is the difference between a submission that goes through and one that bounces. For a walkthrough aimed specifically at email, see our guide on how to compress a PDF for email.
The three levels map to concrete settings. Less Compression is lossless: it removes unused and duplicate objects and recompresses internal streams, so no pixel changes and the saving is usually modest. Recommended re-encodes every embedded image larger than 64x64 pixels as JPEG at quality 75 and scales down any image whose longest side exceeds 2400 pixels. Extreme Compression uses JPEG quality 50 and a 1200-pixel cap, which reads fine on screen but looks visibly softer when printed. Small images such as icons and logos are left alone at every level.
Frequently asked questions
How much will my PDF be compressed?
It depends on the content. PDFs dominated by large photos or scans usually shrink substantially at Recommended or Extreme, because those levels re-encode and downscale the images. Text-and-vector PDFs shrink far less: there are no large images to work on, so only the lossless cleanup applies. For very large PDFs, try splitting into smaller parts first, then compress each part individually.
Is it safe to upload my PDF for compression?
Files are processed on our server using MuPDF and removed once the download is delivered. See our processing model for transport, retention, and logging specifics.
What is the maximum file size?
The maximum file size for PDF compression is 50 MB. If your PDF is larger, try splitting it first with the Split PDF tool, compressing each part, then merging the results.
Will compression affect the text or images in my PDF?
Text, vector graphics, and fonts are never re-encoded at any level. Less Compression changes no pixels at all. Recommended and Extreme re-encode embedded images as JPEG, so photos can lose some fine detail; Extreme also reduces image resolution, which is most noticeable when the document is printed.
How do I compress a PDF for email?
Upload your PDF, keep the Recommended level, and click Compress. Gmail and Yahoo accept attachments up to 25 MB and Outlook.com up to 20 MB, but email encoding enlarges attachments by about a third in transit, so leave headroom below the limit. If the result is still too large, try Extreme Compression, or split the PDF into smaller parts and send them separately.
Can I compress a scanned PDF without losing readability?
Usually, yes. Scanned pages are stored as full-page images, so they respond well to recompression. Recommended keeps scans up to 2400 pixels on the long side, about 220 pixels per inch on a letter-size page, which is comfortable for on-screen reading. Extreme caps pages at 1200 pixels, about 110 pixels per inch, which keeps normal body text readable on screen but can blur small print.
Why is my compressed PDF larger than the original?
It can happen. Recommended and Extreme re-encode every image above 64x64 pixels as JPEG, and an image that was already stored compactly, such as flat line art or a heavily compressed JPEG, can come out larger. PDFs that are already well optimized also leave little for the lossless cleanup to remove. If the result is not smaller, keep your original or try Less Compression.
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