1Drop your PDF documents into the box above, or pick them from your device — there is nothing to install and no account to create.
2Choose how much to compress with the setting shown for this file type: a quality level for images, a bitrate for audio, or a target size or quality level for video.
3Start the job and let the workers re-pack the file; your original is never modified in place.
4Compare the new size against the original, then download the compressed PDF file.
Compress PDF FAQ
What do I get back, and can I control the trade-off?
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A single compressed file per input, at a quality or bitrate level you choose rather than a fixed default. If the result is not small enough, changing the dimensions or the duration will do more than pushing the quality slider further down.
How does Compress PDF actually make the file smaller?
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Concretely, embedded raster images are downsampled to a target DPI, fonts are subsetted to the glyphs actually used and the object streams are rebuilt — text and vector artwork are untouched and stay perfectly sharp. Nothing about it depends on you installing software: the job runs server-side and hands back a finished file.
Is there anything specific to PDF I should know before compressing?
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Yes — a PDF is an object graph, not a page image, so text stays selectable and vectors stay sharp no matter what happens to the raster content inside it. It is worth knowing before you overwrite an original you might need again.
What is the most common mistake when compressing PDF documents?
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Compressing the same file repeatedly. Each pass on a lossy format is a fresh generation of loss and the savings shrink while the damage accumulates. Go from the original to your target in one step, and keep the original.
What can I upload to Compress PDF?
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Any standard PDF, including ones produced by a scanner, by a word processor or by a print driver. Files with an owner password that only restricts editing are handled; files that need a user password to open are not, and we do not attempt to break encryption.
Is there a file size limit on Compress PDF?
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Yes: free use has a size limit per document, and the page tells you when a file is over it; Ghostscript and qpdf do the work. Scanned PDFs are the usual thing that exceeds it, and compressing the document first is normally enough to bring it back under.
Will Compress PDF lower the quality of my PDF documents?
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Text and vector artwork are objects rather than pixels, so they stay perfectly sharp at any zoom no matter what happens. Only the embedded raster images can degrade, and only if the operation you chose resamples them.
Can I run Compress PDF on several PDF documents at once?
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Yes — upload the set and they process in parallel under one set of settings, which is the point of doing a document workflow here rather than clicking through a desktop reader.
Why does a EPUB site host Compress PDF?
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EPUB.to is built around the open eBook format — XHTML in a zip, reflowable by design, and readable on hardware nobody has thought about the layout for. A book is a zip full of markup, images and fonts, so almost every job people bring to an eBook site is really a job on one of those things. Compress PDF runs on the same upload and the same account as the conversions because that is where it is needed.
What should I do with the result once Compress PDF is finished?
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The converter on this site moves books between EPUB, MOBI, AZW3, PDF and DOCX, so a title ends up on whatever hardware is actually going to read it. Doing that after Compress PDF means the conversion is made from the version you settled on, not from the one you were still fixing.
Is Compress PDF here the same tool the sibling sites run?
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The engines are shared — the same toolchain, the same workers, the same limits. What a EPUB site adds is a view on reflow: which of these operations a reflowable book genuinely supports, and which ones only make sense on the fixed-layout media inside it. It also starts from one fact about the format this site is named after: the book is a zip of XHTML with a manifest, so the text costs almost nothing and every decision that matters is about the embedded images and font subsets.
Do I need an account, and does anything get kept?
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No account is needed. Uploads and results are kept for about 24 hours, which leaves time to download the result, and are then deleted automatically; nobody reads, lists or indexes them. Several files in one job need a paid plan.
