How much will my PDF shrink?

Results vary. PDFs with many unused objects or unoptimized cross-references may see noticeable reductions. Image-heavy PDFs typically see little change because images are not re-encoded.

Does this affect PDF quality?

No. The tool only removes unused objects and optimizes internal structure. All visible content — text, images, and layout — is preserved.

Why is the output size sometimes larger?

pdf-lib re-serializes the entire PDF structure. If the original was already tightly packed with no unused objects, the new cross-reference streams may add a small overhead.

PDF Compress

Re-serialize and optimize PDF structure to reduce file size.

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FAQ

How much will my PDF shrink?: Results vary. PDFs with many unused objects or unoptimized cross-references may see noticeable reductions. Image-heavy PDFs typically see little change because images are not re-encoded.
Does this affect PDF quality?: No. The tool only removes unused objects and optimizes internal structure. All visible content — text, images, and layout — is preserved.
Why is the output size sometimes larger?: pdf-lib re-serializes the entire PDF structure. If the original was already tightly packed with no unused objects, the new cross-reference streams may add a small overhead.

PDF Compress uploads your PDF and re-serializes it with pdf-lib to perform structural optimization: removing unused objects, compressing cross-reference streams, and eliminating redundant data. Results vary — the tool does not re-encode images or apply lossy compression. For image-heavy PDFs, savings may be minimal.