ZANCTA

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Compress PDF — reduce size locally

Rewrites the PDF with object streams in your browser. This does not recompress embedded images, so size may stay the same or grow. The original and output sizes are always shown.
Local processing

Tool details

local boundary
Formats
PDF
Limits
Up to 50 MB per file · 1 file
Processing
Processing stays in this browser after the page loads.
Result
Download or copy the result from this tab. Nothing is stored on ZANCTA.
Local processing

Processed in this tab. File bytes are not uploaded. How local processing works

Max 50MB/file, 1 files. Password-protected PDFs aren't currently supported. Compression rewrites the PDF with object streams. Embedded images are not recompressed; size may stay the same or grow.

Free, no upload — pass it on:

Before you start

A clear path through Compress PDF.

Review the input, the visible limits, and the expected result before you choose a file. The workspace remains the primary place to do the task.

  • Check the input

    PDF supported · up to 50 MB per file · up to 1 file.

  • Keep the boundary visible

    Selected file bytes are processed in this browser for this supported local workflow.

  • Review the result

    Wait until the tool finishes, inspect the output, then download or clear the workspace.

Related reading: How PDF compression actually works here

FAQ

Will quality drop?
Embedded images are not recompressed. The file is rewritten with object streams; we report the actual size, which may not shrink.
Why did my PDF not get smaller?
Image-heavy files stay large because pictures are not transcoded. See the Compress PDF without uploading guide.

Processing runs locally in your browser — no upload. Outputs are generated on-device. For the privacy boundary see the local processing guide.