Compress PDF
Compress one or up to 20 PDF files online. Reduce every PDF separately and download multiple compressed results together in one ZIP archive.
✓ Batch compress up to 20 PDFsReduce multiple PDF files in one batch
Select up to 20 PDF files. MarsPDF compresses each document separately and lets you download every result in one ZIP archive.
Drop your PDF files here
Up to 20 PDFs • Max 100 MB per file
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Secure
Your files are transferred and processed securely over encrypted HTTPS.
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 One or Multiple PDF Files Online
Use MarsPDF to compress one PDF or batch compress up to 20 PDF files online. When you select multiple documents, each PDF is optimized separately and all compressed results are delivered in one ZIP archive.
Batch PDF compression saves time when reducing invoices, reports, contracts, scanned documents, or many email attachments. Smaller PDF files are easier to upload, store, email, and share.
How to Compress a PDF
Upload Your PDF Files
Select or drag and drop one PDF or up to 20 PDF files at once.
Compress Automatically
MarsPDF reduces the file size while keeping the document readable.
Download File
Download a single result as PDF or multiple compressed files together in one ZIP archive.
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.
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 safely discarded after processing.
Can I reduce multiple PDF files at the same time?
Yes. You can select up to 20 PDF files in one batch. Each file is compressed separately and every result is downloaded inside compressed-pdfs.zip.