Compress PDF
Try structural/object-stream optimization and compare the output size. Files are processed locally in your browser.
Drop your PDF here to process
or click the button below to browse your files
What this compressor actually changes
A structural rewrite
Compress parses the PDF with pdf-lib, then saves it with useObjectStreams enabled. This can pack eligible PDF objects more efficiently. It does not explicitly downsample or recompress images, offer a quality slider, or target a specified number of kilobytes.
The result can be smaller, nearly unchanged or larger. Image-heavy files may have little structural overhead to remove, while a small file can gain overhead during rewriting. Compare the original and resulting byte sizes shown by the tool rather than assuming that every download is smaller.
What our limited checks show
Internal Node tests observed a substantial reduction for one text-heavy synthetic fixture, much smaller changes for two real documents, and growth for small or already-optimized controls. These are individual file observations, not typical savings or a promise about your PDF.
Reopening and text/geometry checks are not proof of universal lossless preservation. Rewriting can change producer/modification metadata, PDF version or linearization. Signatures, interactive behavior and whole-document visual fidelity were not established by those checks.
Decide whether to keep the result
Keep the original, inspect the reported sizes, and reopen the output. Check critical pages, text and document features before replacing a working copy. If an attachment is still too large, choose fewer pages with Split or change export settings in the source application; Compress has no target-size setting.
Parsing, saving and the size comparison occur locally without a compression-backend upload. Website resources still load over the network. Encrypted, damaged or memory-intensive PDFs can fail; use an unencrypted copy you are authorized to process.
Frequently asked questions
Compress PDF Online — Free & Private
PDFcraft processes your PDF locally in your browser using object-stream serialization. No account is required. Compare the original and output sizes before downloading; the result may be larger.
What does the Compress PDF tool do?
The tool loads and saves your PDF using structural/object-stream optimization. It does not explicitly downsample or recompress embedded images, and does not guarantee deduplication or a smaller file. Review the output and keep your original; rewriting a PDF can affect signatures and document-level features.
How to compress a PDF online — step by step
- Click Select File or drag your PDF into the upload area
- Your PDF is processed locally in the browser, without a PDF-processing upload backend
- Processing starts automatically when you select a file
- See the original vs new file size comparison
- Click Download to save the compressed PDF
Why use PDFcraft to compress PDFs?
- Free to use — practical limits depend on your device and browser
- No file uploads — compression happens locally in your browser
- No explicit image recompression — the tool rewrites the PDF structure
- No sign up — open the tool and start immediately
- Try on mobile — browser support and usable file sizes vary on iPhone and Android
- Local processing — processing time depends on your file and device
Common use cases for compressing PDFs
- Try reducing PDFs to meet email attachment limits
- Compare output size against your messaging service’s current limits
- Compress PDFs for website upload forms and portals
- Reduce storage space for archived documents
- Compress scanned documents for faster sharing
- Make PDFs load faster when embedded on websites
Is compressing PDFs online safe?
Files are processed locally in your browser. This tool does not upload your document to a processing server. Keep your original and review the generated PDF before using it.
Wondering how much this tool will actually shrink your file? Learn how to measure compression results for your own PDF →