How much will my PDF shrink?

Results vary widely. PDFs with uncompressed object streams may shrink by 50-70%. PDFs already optimised may see only a few KB reduction.

Does it reduce image quality?

No. This tool only applies structural object stream compression. Image data is not re-encoded or downsampled.

Why didn't my PDF shrink much?

Your PDF was likely already saved with compression enabled. This tool cannot further compress already-optimised PDFs without re-encoding images.

Are my files uploaded to a server?

No. pdf-lib runs entirely in your browser. Your PDF never leaves your device.

PDF Compressor

Re-save a PDF with object stream compression to reduce file size — no image re-encoding.

How to use this tool

1Click the upload zone and select a PDF file.
2Click 'Compress PDF' to re-save with object stream compression.
3Download the compressed result and compare the file size.

About PDF Compressor

Not all PDF compression is equal. This tool applies pdf-lib's object stream compression, which packs the PDF's internal object table more efficiently without touching image data or re-encoding content. PDFs that were saved without compression (common from older software or print-to-PDF drivers) can shrink significantly. PDFs already saved with compression may see little change. The tool loads your PDF, re-saves it with useObjectStreams: true, and triggers a download. Results vary widely — a 10 MB uncompressed PDF might shrink to 3 MB, while an already-optimised PDF might only shrink by a few KB. Runs entirely in your browser using pdf-lib.

Frequently asked questions

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