Compress PDF
Compress PDF files online for free. Reduce PDF file size while keeping documents clear, readable, and easy to share.
Drop your PDF file here
Max file size: 100 MB
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Secure
Your files are transferred over secure HTTPS and automatically deleted after 1 hour.
Fast
Compress your PDF files in seconds with our high-performance servers.
Easy to Use
Simple and intuitive interface makes compressing PDFs easy and quick.
Compress PDF Files Online
Use MarsPDF to compress PDF files online and reduce document size directly in your browser. A smaller PDF file is easier to upload, email, store, and share without installing any software.
PDF files can become large when they contain scanned pages, high-resolution images, graphics, forms, or many pages. Our Compress PDF tool helps optimize your document and make the file size smaller while keeping it clear and readable.
How to Compress a PDF
Upload Your PDF
Select or drag and drop the PDF file you want to compress.
Compress Automatically
MarsPDF reduces the file size while keeping the document readable.
Download File
Download your compressed PDF and review the final result.
Why Reduce PDF File Size?
Reducing PDF file size is useful when your document is too large for email attachments, online forms, document portals, school submissions, job applications, or cloud storage. A compressed PDF is faster to upload and easier to share.
Compression is especially helpful for scanned documents, image-heavy PDFs, reports, invoices, certificates, contracts, and forms that need to stay readable but smaller in size.
Does PDF Compression Affect Quality?
PDF compression may slightly reduce image quality depending on the content of the file. The goal is to reduce file size while keeping the document readable and useful.
Text-based PDFs usually keep their quality well, while scanned or image-heavy PDFs may show a small difference after compression. Always check the compressed file before using it for important purposes.
Secure Online PDF Compression
Uploaded files are processed only for the selected tool and are not used for any other purpose. Files are automatically deleted from our servers within 1 hour after processing.
MarsPDF uses secure HTTPS connections to help protect file transfers between your browser and our servers.
Frequently Asked Questions
Is the Compress PDF tool free?
Yes. You can use MarsPDF to compress PDF files online for free.
Do I need to install software?
No. The Compress PDF tool works directly in your browser. You do not need to install any desktop software or browser extension.
Why is my PDF file so large?
PDF files can become large because of scanned pages, high-resolution images, embedded fonts, forms, graphics, or many pages.
Can I compress scanned PDF files?
Yes. Scanned PDF files can usually be compressed, but the final size depends on the image quality and structure of the original document.
Are my uploaded files safe?
Uploaded files are processed only for compression and are automatically deleted from our servers within 1 hour after processing.