How much can you compress a PDF without losing quality?

It depends on what is inside. A scanned or image-heavy PDF can often drop 60–80% because compression re-encodes its page images at a lower resolution and JPEG quality. A mostly-text PDF may barely shrink — there is little to compress once you reach the embedded fonts and page structure. The Medium preset (about 200 DPI) is the usual balance between size and on-screen legibility.

Is it safe to compress a PDF online?

With this tool the compression runs in your browser through a background Web Worker, so the file is processed on your device rather than sent to a server. Note that the process rebuilds each page as an image, so the output PDF no longer has selectable or searchable text — keep the original if you need that.

Why is my PDF still large after compression?

If the document is mostly text with few images, most of its size is embedded fonts and the PDF structure itself, and image compression cannot reduce those. Splitting the document and keeping only the pages you need often gets further toward a strict size limit than compressing harder.

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Compress PDF tools

Reduce PDF file size for seamless email attachments and fast web sharing without sacrificing reading clarity.

A PDF's file size comes almost entirely from what's embedded inside it — high-resolution images, scanned pages stored as full-resolution pictures, and embedded fonts. Compression trades some of that image detail for a smaller file, which matters most for scanned or image-heavy documents; a mostly-text PDF may not shrink by much no matter how aggressive the setting.

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Compress PDF tools — questions

How much can you compress a PDF without losing quality?: It depends on what is inside. A scanned or image-heavy PDF can often drop 60–80% because compression re-encodes its page images at a lower resolution and JPEG quality. A mostly-text PDF may barely shrink — there is little to compress once you reach the embedded fonts and page structure. The Medium preset (about 200 DPI) is the usual balance between size and on-screen legibility.
Is it safe to compress a PDF online?: With this tool the compression runs in your browser through a background Web Worker, so the file is processed on your device rather than sent to a server. Note that the process rebuilds each page as an image, so the output PDF no longer has selectable or searchable text — keep the original if you need that.
Why is my PDF still large after compression?: If the document is mostly text with few images, most of its size is embedded fonts and the PDF structure itself, and image compression cannot reduce those. Splitting the document and keeping only the pages you need often gets further toward a strict size limit than compressing harder.

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