Tools

Compress PDF

Compress PDF files for free in your browser. Choose lossless optimisation or JPEG quality 75 for compatible embedded images, then download the result only when it is smaller.

Your PDF is processed in this browser. It is not uploaded or stored.

One PDF, up to 50 MB and 300 pages. Encrypted, password-protected and digitally signed PDFs are not supported.

Drop one PDF here

Compression method

Lossless optimisationRecompresses compatible streams and reorganises PDF objects. Text, vector artwork and embedded images are not intentionally changed.Smaller embedded imagesConverts or recompresses compatible embedded images at JPEG quality 75, including some existing JPEGs. It can reduce image quality and may not affect every image.

Neither method rasterises whole pages or removes document features on purpose. Results vary with the way the source PDF was created.

The browser stops the compression engine if it has not finished within 120 seconds.

This tool runs qpdf in a dedicated browser worker. It can reorganise PDF objects, recompress compatible streams and optionally recompress supported embedded images. It does not turn complete pages into images. The tool creates a download only when the processed file is smaller than the original.

How to use this tool

Choose one PDF of up to 50 MB and 300 pages. The tool checks its format, page count, encryption and detected digital signatures in your browser.
Use Lossless optimisation first when text clarity and existing image data must remain unchanged. It recompresses compatible streams and reorganises PDF objects.
Choose Smaller embedded images when a small loss of image quality is acceptable. This adds JPEG quality 75 recompression for compatible embedded images; it does not downsample every image.
Run the compression. If the result is smaller, compare the before and after sizes, download technine-compressed.pdf and check the document before replacing the source file.

Ways to use it

Reduce an email attachment: Try lossless optimisation first, then use embedded-image recompression if the PDF is still too large and its image quality can be reduced.
Make a report easier to share: Optimise a report that contains repeated or inefficiently compressed PDF objects. The actual saving depends on how the report was exported.
Shrink a scan-based PDF: Use the embedded-image method for PDFs made from compatible JPEG scans. Images stored in other ways may not change, and this tool does not reduce their pixel dimensions.

Supported files and limits

The tool accepts one PDF up to 50 MB and 300 pages. It rejects encrypted, password-protected and detected digitally signed PDFs. A signed file must remain unchanged if its signature is to stay valid.
Compression runs locally in a WebAssembly worker. The selected file is not uploaded or stored, but the browser needs enough memory for the input, the compression engine and the result. A file within the stated limit may still fail on a device with limited memory.
Each compression job stops after 120 seconds. Closing or refreshing the page also clears the generated download because the website does not retain it.
Lossless optimisation does not guarantee a smaller file. A PDF that is already optimised may stay the same size or become slightly larger, in which case the tool does not offer the candidate for download.
The embedded-image method can convert compatible non-JPEG images to JPEG and recompress some existing JPEGs at quality 75. It can introduce visible compression artefacts, does not downsample image dimensions and may leave unsupported image encodings unchanged.
The tool is designed to retain PDF document structures rather than flattening the pages. PDF features vary widely, so check pages, text, links, forms, bookmarks, attachments and print output before replacing an important original. Engine warnings are shown with the result.
Compression is not document sanitisation. JavaScript, links, attachments and other active content are not intentionally removed. Do not use this tool to make an untrusted PDF safe to open.
A rewrite can change object numbers, byte layout, document IDs, linearisation and the effective PDF version. PDF/A, PDF/X and other conformance profiles are not guaranteed to remain valid.

Common questions

Is my PDF uploaded to a server?

No. The browser reads the selected PDF and runs the compression engine locally. The source and result are not stored by the website.

What is the difference between the two compression methods?

Lossless optimisation reorganises PDF objects and recompresses compatible streams without intentionally changing embedded image data. Smaller embedded images can convert compatible images to JPEG and recompress some existing JPEGs at quality 75, so image quality can decrease.

Why did the tool not create a download?

The processed candidate was not smaller than the source. This often happens when a PDF is already compact or its largest content cannot be recompressed by the selected method. The candidate is discarded so you do not replace the original with a larger file.

Will image compression make every PDF much smaller?

No. It only affects compatible embedded images. It does not lower image dimensions, and it may not change images that use unsupported encodings or that are already compressed efficiently.

Can I compress an encrypted or signed PDF?

No. Encrypted and password-protected files are not supported. Detected digitally signed PDFs are also rejected because rewriting the file would invalidate its signature.

Will links, forms, bookmarks and attachments remain?

The compression settings do not intentionally remove those structures, but PDF files can use them in many ways. Keep the source and verify every important feature in the downloaded file, especially when the engine reports a warning.