How to Compress a PDF and Reduce File Size (5 Ways)
Learn five ways to compress a PDF, from a free browser tool to Mac Preview and Word export. See real size results and shrink yours today.
Why PDF Files Become Large
PDF size can grow because of embedded images, scanned pages, fonts, vector content, metadata, and other internal resources.
How PDF Compression Works
Compression can reduce the amount of data needed to represent pages. Image-heavy PDFs often respond differently from text-heavy PDFs.
How to Compress a PDF With MergeImagePDF
Open the Compress PDF tool, choose the available quality and rendering options, and compare the output with the original.
Does PDF Compression Reduce Quality?
It can. A smaller file may require lower image quality or lower rendering resolution. For this reason, the output should be checked before final use.
PDF Compression vs ZIP Compression
ZIP compression stores one or more files in a compressed archive. PDF compression changes or re-encodes resources inside the document itself.
What the Browser Tool Does to Your PDF
The Compress PDF tool rebuilds every page as an image with your chosen quality. That shrinks scans and photo-heavy files well. But the text in the new file is part of the picture, so it can no longer be selected or searched. Keep your original when you need searchable text.
Which PDFs Shrink the Most
Files that are large because of images shrink most: scans, photo decks and brochures. Documents that are mostly text are usually small already and may not get smaller.
Compress a PDF on a Mac With Preview
Preview can shrink a PDF and keep it as a normal document. Open the file, choose File > Export, pick Reduce File Size from the Quartz Filter menu and save. Apple describes this in Reduce the size of a PDF in Preview. Check the result, because the filter can lower image quality noticeably.
If the PDF Is Still Too Large
- Try the Higher compression setting or the Compact render scale.
- Split the document into parts with Split PDF.
- Remove pages you do not need before compressing.
Frequently Asked Questions
Can I compress a PDF without losing quality?
Some quality is usually traded for size. Choose a higher quality setting to keep more detail, and compare the result with the original.
Is compressing a PDF safe for private files?
The browser tool does not upload your file.
Try it now: Compress PDF — free, in your browser.