Compress PDF Files Online
Reduce PDF file size while optimizing for maximal quality. Choose from high compression, balanced, or best quality modes.
How to Compress a PDF — Step by Step
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1
Upload your PDF
Click the upload area or drag your PDF onto it. Files up to 150 MB are supported.
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2
Choose a compression level
Select low (best quality, ~20% smaller), balanced (recommended for most uses, ~50% smaller), or high (maximum reduction, up to 70% smaller).
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3
Click Compress and download
Download the compressed file and open it to verify that text and any critical details (charts, stamps, signatures) are still readable.
Choosing the Right Compression Level
Most oversized PDFs are large because of embedded images — particularly high-resolution photos or scanned pages. Compression works by reducing the quality of those embedded images. The text and structure of the document are not affected; only image data changes.
Low compression is the right choice when print quality matters — brochures, certificates, or reports with charts where fine detail must stay sharp. Balanced compression handles most everyday documents: invoices, contracts, forms, and reports that will be read on screen. High compression is useful when meeting a strict size limit (such as a portal's 5 MB limit) and visual quality is secondary.
If your PDF is still too large after high compression, the content itself needs attention. Use Organize PDF to remove blank or unnecessary pages, or use Split PDF to divide the document into smaller sections. Compressing a leaner file always yields better results. Read the full PDF compression guide for more detail.
Frequently Asked Questions
Is the PDF compressor tool really free?
Yes, our PDF compressor is free to use within the listed upload limits. No registration is required and no watermarks are added.
How much can I compress a PDF file?
Compression depends on your PDF content. High compression can reduce size by up to 70%, balanced mode typically reduces by 50%, and low compression preserves quality while reducing by about 20%.
Are my PDF files safe when compressing?
Absolutely. We use SSL encryption for all file transfers. Your PDFs are processed securely and automatically deleted from our servers after a short period. We never store or share your files.
Which compression level should I choose?
Choose high compression for email and messaging (maximum size reduction). Use balanced mode for general use and official work (recommended). Select low compression for printing and documents requiring highest quality.
What file size limits apply for PDF compression?
You can compress PDF files up to 150MB in size. For larger files, consider splitting the PDF first or using our other tools to manage file size.