Large PDFs slow down email, exceed upload limits, and consume storage unnecessarily. PDFStream's PDF compressor reduces file size directly in your browser — no upload, no waiting, no quality guesswork. The compression works by optimizing the internal PDF structure and downsampling embedded images where possible, targeting a meaningful size reduction while keeping the document readable and printable. A 10MB scanned report often compresses to under 3MB. A PDF with high-resolution product photos might shrink from 25MB to 8MB without visible degradation at normal viewing or print sizes. Typical use cases include compressing a portfolio before sending it to a client, reducing a presentation PDF before uploading to a shared drive, preparing a scanned document for email when the original exceeds the attachment limit, or optimizing a batch of archived reports to free up storage. Because compression happens locally, there's no risk of a confidential document passing through a third-party server. The compressed file is ready to download immediately — no waiting for a server-side queue.

How-to

1
Select File
Upload the PDF file you wish to compress.
2
Choose Level
Select your desired compression level. Medium is recommended.
3
Compress
Click 'Compress PDF'.
4
Download
Download your smaller PDF.

Frequently Asked Questions

How much will it compress?▼

It depends on the content. PDFs with many images can be reduced by 50% or more with 'High' settings. Text-heavy PDFs may have less reduction.

Will quality be damaged?▼

'Low' compression keeps virtually original quality. 'High' might reduce image quality, but text remains perfectly clear.

Can I re-compress?▼

Yes, but there are diminishing returns if the file is already optimized.

Which level should I choose?▼

We recommend 'Medium' for a perfect balance of quality and size.

Is text quality maintained?▼

Yes, text is stored as vectors and will remain sharp regardless of compression settings.

How small can it go?▼

Files with many images can often be reduced by 50-80%.

Will 'High' compression ruin images?▼

It lowers resolution. It's great for viewing on screens, but may be suboptimal for high-quality printing.

Can I compress already compressed files?▼

If a PDF is already optimized, further compression will have little effect.

Can I preview before downloading?▼

We don't provide a visual preview, but you can see the file size reduction before downloading.

Can I compress multiple files at once?▼

Currently, we process one file at a time. For multiple files, we recommend merging them first.

Last updated: June 26, 2026

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