Compress PDF
Reduce redundant PDF structure locally in your browser. Maximum lossless removes duplicate page content without rasterizing pages. Compare actual savings; already optimized PDFs may not shrink.
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Processed in your browser, not uploaded.
Processed locallyFiles and text are processed in your browser and are not uploaded to our servers.Learn more
How to compress a PDF
- 01
Choose a PDF
Select one unencrypted PDF from your device. Check the page thumbnails, page count and original size.
- 02
Choose a compression mode
Standard prioritizes speed. Maximum lossless also finds duplicate page-content streams. Separate Images modes use lossy JPEG quality of 92%, 75% or 50% without changing pixel dimensions.
- 03
Compress, compare and download
Compression runs locally. Compare original and output sizes, then download your document with -compressed added to its name. If it did not shrink, the result says so.
What this PDF compressor changes
Only the optional lossy Images modes selectively re-encode supported opaque, 8-bit RGB JPEG images and RGB images stored raw or with basic Flate compression. A replacement is used only if its image data is smaller. Tiny images, masked or transparent images, complex image encodings and images above 16 megapixels are left unchanged.
All modes compress unfiltered streams, remove unreachable objects and write compact object streams. Maximum lossless also shares identical decoded page-content streams after checking their dictionary semantics and actual bytes. Reachable fonts, metadata, color profiles, links, forms and accessibility structures are retained. Arbitrary resource dictionaries are not merged.
Quality and file-size tradeoffs
Standard and Maximum lossless do not reduce image quality. The explicitly labelled Images modes are lossy, even at high quality. Inspect small text in scans before sharing. There is no downsampling or target-DPI adjustment.
Repetitive text or vector documents can benefit substantially from duplicate-content removal. Unique or already optimized documents may shrink very little. Only a validated smaller rewrite is returned; otherwise the original is kept. A specific size such as 1 MB cannot be guaranteed. Large documents depend on available browser memory.
Private processing
Your PDF is processed locally in your browser and is not uploaded to WeDoConvert servers. The file and its name, size, page count, metadata, compression settings and output are not sent to analytics. Keep your original, especially if it contains digital signatures.
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Frequently asked questions
How does PDF compression reduce file size?
Maximum lossless removes duplicate page-content streams and unreachable objects, and packs the remaining structure compactly. Standard skips deduplication to prioritize speed. Optional Images modes also recompress supported RGB images with quality loss.
Will compression reduce PDF quality?
Standard and Maximum lossless retain image data quality. Only the Images modes use lossy JPEG encoding. Text and vector graphics are never rasterized. Inspect the downloaded PDF before using it.
Why did my PDF barely get smaller?
Text, vectors and already compressed images may have little room for improvement. Transparent, masked, non-RGB or otherwise unsupported images are retained, as are images above the memory limit.
Can text and links remain selectable?
Yes. Pages, text, links, annotations and forms are retained in the existing document structure. Scanned text that was not selectable before remains an image; this tool does not add OCR.
Are my PDF files uploaded?
No. Your PDF is processed locally in your browser and is not uploaded to WeDoConvert servers.
Why can a compressed PDF be larger?
A rewrite can add overhead, so the tool returns it only if it validates and is smaller. Otherwise you see a no-reduction message and can download the unchanged original.
Does compression affect forms or signatures?
Forms are not flattened and their existing appearances are retained. Rewriting a signed PDF can invalidate digital signatures; detected signature fields trigger a warning. Signature detection is not verification. Keep signed originals.
Can I compress an encrypted PDF?
Encrypted or password-protected PDFs are unsupported. Save an unprotected copy using an authorized PDF reader first.