HelperCratePDF Compress
Reduce PDF size by re-saving with object streams and stripped metadata.
Your files never leave your device. Everything runs in your browser.
What PDF Compress does
PDF Compress reduces a PDF's size by re-saving its internal structure with object streams and, optionally, stripping standard metadata such as title, author, creator and keywords.
It targets file bloat that comes from document overhead: files edited many times, exports carrying redundant objects, or documents whose metadata reveals more than intended. It is a structural optimiser, not an image re-compressor — the tool says as much on the page itself.
That distinction matters. A scan made of large photos will barely shrink here, because the images are left exactly as they are. For image-heavy files, the real savings come from reducing the images before the PDF is built.
How to use PDF Compress
- Drop a PDF onto the dropzone.
- Leave Strip metadata checked to clear the title, author, subject, keywords, producer and creator fields, or uncheck it to keep them.
- Click Compress PDF.
- Read the result: the card shows the exact before and after sizes, and a percentage only when the file really got smaller.
- Download the compressed copy and compare it with the original before replacing anything.
Features
- Re-saves the PDF with object streams enabled, which can reduce structural overhead.
- Optional metadata strip covering title, author, subject, keywords, producer and creator.
- Reports exact before/after byte sizes and shows a percentage only when a saving occurred.
- Honest scope: no image downsampling, no re-encoding, no forgotten quality trade-off.
- Output uses a -compressed suffix so your original file on disk is untouched.
- Works fully offline in the browser with pdf-lib.
Tips and common mistakes
- Compare the compressed file with the original in a viewer before replacing anything; the download is always a new file.
- If a portal rejects an oversized PDF, stripping metadata is the quickest first attempt.
- For scans, compress the images before building the PDF — post-processing the PDF cannot undo oversized images.
Frequently asked questions
How much smaller will my PDF get?
It depends on the file. Documents with heavy structural overhead, redundant objects or bloated metadata can shrink by a satisfying margin. Already-optimised or image-heavy PDFs may barely change, and occasionally grow by a few bytes. The tool never promises a percentage.
Why did my scanned PDF hardly change?
Scans are mostly large embedded images, and this tool deliberately does not downsample or recompress them. To shrink a scan, reduce the image resolution first — for example compress the photos with the Image Compressor, then rebuild the document with Images to PDF.
What exactly does “Strip metadata” remove?
The standard document information fields: title, author, subject, keywords, producer and creator. Page content, annotations and bookmarks are untouched.
Can compressing change how the pages look?
No. The visible content is neither re-rendered nor re-encoded; only the file's internal structure and, if you ask, the information fields change.
Can the result be larger than the original?
Yes, occasionally — for example when the source was already packed optimally. The result card shows the exact numbers and withholds the percentage in that case, so you can simply keep whichever copy suits you.
Is it safe to run on a digitally signed PDF?
No — re-saving changes the bytes of the file, which invalidates cryptographic signatures. Avoid it on signed documents you still need verified. Visual signatures (an image placed on the page) are not affected.
Related pdf tools: Images to PDF, PDF to Images, PDF Metadata Editor, Image Compressor.
Compression happens on your device with pdf-lib; the file is never uploaded.