Compress PDF
Reduce the size of a PDF file while preserving readability.
About Compress PDF
The Compress PDF tool shrinks PDF files by downsampling embedded images, re-encoding them and removing redundant data — while keeping text sharp and selectable. Image-heavy PDFs often shrink 50–90%, which gets scans and brochures under the 5–25 MB caps common on email and government portals.
Pick a quality level to trade size against image crispness, and re-run at a lower setting if the result is still too large. A presentation full of photographs offers much more room for reduction than a digitally generated invoice containing mostly text and vector lines, so the final percentage depends on what is embedded in the source.
The compressor creates a new copy rather than modifying the original. That makes it practical to compare size and readability, especially around small labels, diagrams and scanned signatures, before choosing which version to submit or archive.
How Compress PDF works in practice
- 1Drop your PDF onto the upload area.
- 2Pick a quality level — lower quality means smaller files.
- 3Click "Compress PDF" and compare the new size.
- 4Download the smaller PDF, or re-run at a lower quality if needed.
Jobs this tool is built for
- Reduce a scanned application below a government portal or university upload limit.
- Shrink a photo-heavy brochure so it can be attached to an email without a cloud-storage link.
- Optimise downloadable reports for a website where large files are slow on mobile connections.
- Create a lighter review copy of a long scan while retaining the high-resolution original for records.
What you can do here
- Adjustable quality vs size trade-off
- Automatic image downsampling and re-encoding
- Removes duplicate fonts, metadata and unused objects
- Text stays sharp and selectable
- Works with scanned and native PDFs
Limits and honest caveats
- Most size savings come from re-compressing images, so image-heavy PDFs shrink the most while text-only PDFs may barely change.
- Higher compression can slightly reduce image sharpness — check the result if the document contains detailed graphics.
- Compression runs in your browser, so your PDF is not uploaded to a server.
Common questions about Compress PDF
How much can I shrink my PDF?
Image-heavy PDFs often shrink 50–90%; text-only PDFs may only reduce 10–30%.
Can I compress a PDF twice?
You can, but the second pass gives diminishing returns and may visibly reduce image quality.
Why did a text-only PDF barely shrink?
Text, vector graphics and embedded fonts are already compact. Most dramatic savings come from downsampling and re-encoding large images.
Will text remain searchable and selectable?
Yes for text that was selectable in the original. Compression does not perform OCR, so text inside a scanned image remains an image.
This page was written by the ToolSink team to explain how Compress PDF works on this site — it is not syndicated, scraped, or spun from another publisher. How we write tool guides · Site updates · About ToolSink.
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