Compress PDF
Try to reduce PDF file size for email, web, or storage. Choose a compression setting and review the downloaded document before using it.
Upload a PDF to compress
Results vary by document; scanned or image-heavy PDFs may show larger changes. Files are stored temporarily for processing, so download the result promptly.
Drag and drop a file here, or click to browse.
Watch: How to Compress a PDF Online
This short video shows how to upload a PDF, choose a compression level, run the compression process, and download the resulting document using PDF Toolbox Online.
How to Compress PDF Files for Free
Try to reduce the size of one PDF with a choice of three compression settings. Results vary with the document, and stronger compression can reduce image quality or change parts of the PDF, so inspect the downloaded file carefully.
Select File
Choose the PDF document from your device or drop it directly into the compression box.
Compression Level
Choose 'More Compression,' 'Balanced,' or 'Higher Quality' based on the tradeoff you want to test.
Optimize
Click 'Compress PDF' to rebuild the document with the selected Ghostscript compression preset.
Download
Download the result, check the reported file sizes, and verify the document's content and features.
What Happens During PDF Compression?
PDF compression is a complex technical process that goes beyond simply "zipping" a file. This tool uses Ghostscript to generate a PDF 1.4 output with the selected compression preset. During that process, images may be downsampled or recompressed, and fonts or other internal structures may be rewritten. The exact changes depend on the source document.
The three settings provide different size-and-quality tradeoffs rather than a guaranteed reduction. A PDF that is already efficient may not become smaller; in that case, the tool returns the original file data. Always compare pages, text, links, forms, signatures, accessibility, and other important features before replacing the original.
When Should You Optimize Your PDFs?
Large files can exceed email or portal upload limits and take longer to transfer. Compression may be useful in situations such as these:
- Trying to meet an email provider's attachment limit
- Uploading resumes to job application portals
- Submitting government or legal forms online
- Creating smaller working copies of high-resolution scans
- Improving document loading speeds on mobile devices
- Reducing server storage costs for business backups
If you are dealing with an exceptionally massive file, you might also consider using our Split PDF tool to remove unnecessary chapters before compressing the remaining sections.
File Processing and Privacy
Uploads and downloads are sent over HTTPS, which protects data in transit between your browser and the service. Compression occurs on the server, so only upload documents you are authorized to process and avoid especially sensitive material when server processing is not appropriate.
Uploaded and generated files are stored temporarily to support processing and download. Download the result promptly, close the session when finished, and do not use the service as long-term file storage or depend on a particular deletion schedule.
Maximizing Your PDF Experience
Once your file is optimized for size, you may want to refine its contents further. If you've compressed multiple separate documents, you can use our Merge PDF tool to bundle them together into a single, lightweight package.
Is the page order still a bit messy? Our Reorder PDF Pages utility allows you to drag and drop your optimized pages into the correct sequence. For those working with images, converting high-res JPGs to PDF before compression may help create a document for sharing. File size and image quality still depend on the source images and the settings used.
FAQ
Is it possible to reduce a PDF's file size without losing text clarity?
Sometimes, but the result depends on the PDF and the selected setting. Compression can downsample images and rebuild parts of the document, so text appearance, searchability, fonts, forms, links, and accessibility features should be checked in the downloaded file. Keep the original when working with important documents.
How much can I expect to reduce my PDF file size?
There is no fixed reduction percentage. Image-heavy or scanned PDFs may shrink more than PDFs that are already optimized, but the visual tradeoff also varies. If the generated PDF is not smaller than the upload, the tool returns the original file data and reports a 0% reduction.
Why is my PDF still too large for email after compression?
Some PDFs contain images, fonts, graphics, attachments, or other data that cannot be reduced enough for a particular email limit. Try the 'Smaller File' setting and inspect the result. If it is still too large, the Split PDF tool can divide the document, but each recipient will receive separate files.
How secure are my confidential files during the compression process?
Uploads and downloads are sent over HTTPS, and files are stored temporarily on the server for processing and download. Avoid uploading a document you are not authorized to process, download the result promptly, and do not rely on the service as permanent storage or on a specific deletion time.
Can I compress multiple PDF files simultaneously?
No. The current compressor accepts one PDF at a time and returns one PDF. You can process additional files one by one. If you need a single combined document, use Merge PDF separately and review the merged file before deciding whether to compress it.
Do I need to download an app or software to optimize my PDFs?
No application installation is required. You use the tool through a web browser, while compression runs on the server. A current browser, JavaScript, an internet connection, and permission to upload and download files are required; compatibility can vary by browser, device, and file size.