Compress PDF
Compress PDF files to reduce size fast. Shrink and optimise your PDF with adjustable compression levels. Free, secure, no sign-up and no watermark.
🔒 This tool processes your file on our secure server. Files are sent over an encrypted connection.
Reduce PDF file size.
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Try it with sample files
Compare file size and image quality at compression level 5
Use an image-based PDF to see what compression changes before choosing a setting for an upload limit. The sample contains a synthetic colour pattern with fine detail.
Settings and steps
- Download image.pdf, then select it in the file area above. Compression sends the file to the processing server and needs an internet connection.
- Choose 5 under “Compression level (1 = light, 9 = maximum)”.
- Select “Run”, save the downloaded PDF, and compare it with the input and the reference below.
Expected result and checks
Recorded result at level 5: 988,505 → 88,005 bytes. The output opens as a one-page PDF.
Download reference output · compressed-level-5.pdf ↓- Open both PDFs at the same zoom. Compare fine coloured details and edges; a smaller file can contain visibly less image detail.
- Check the actual file size against your destination’s upload limit. A successful download alone does not mean that the limit has been met.
Limits and troubleshooting
- These sizes apply to this sample and recorded run only. Text-based or already-compressed PDFs may shrink less, stay similar in size, or grow.
- If detail becomes unclear, retry the original at a lower level and compare. If the request fails, check the connection and retry with this small sample to distinguish a service issue from a document-specific problem.
Reference results recorded: · View check record (JSON)
Upload one PDF to the compression service and choose a level from 1 to 9. Compression can help reduce image-heavy files, but the result may lose detail or remain above your destination's size limit. Compare the downloaded file's size, page count and appearance with the original. This tool needs a connection and sends the document to the processing server.
How to Compress PDF
- Select the PDF you want to compress in the file area.
- Choose a value from 1 to 9 under Compression level; 5 is selected by default.
- Select Run, save the downloaded file, and compare its size and image detail with the original.
Frequently asked questions
Is this PDF compressor free to use?
The tool is free to use and does not require an account. It processes one PDF per request. Network conditions, service availability and server limits can affect whether a request completes.
What happens to my file after compression?
Your PDF is sent over HTTPS to the processing service, which returns the output for download. The download status is not evidence that all server-side temporary data has been deleted. Read the site's Privacy Policy and follow your organisation's upload requirements.
Will compressing reduce the quality of my PDF?
It can reduce image detail, and the effect depends on the file and setting. Open the original and output at the same zoom and inspect small text, edges and images. If the result is unclear, retry the original with a lower compression level.
How small can my PDF get?
There is no guaranteed reduction or target size. Image-based files may shrink more than files that are already compressed, but some outputs can become larger. The downloadable sample on this page shows one recorded result, not an average for all PDFs.
Can I compress a confidential PDF safely?
Compression uploads the document to a server over HTTPS. Whether that is appropriate depends on your document-handling requirements. If the file must stay on your device, use a compression tool that processes it locally.
Which compression level should I choose?
The available levels are 1 to 9, with 5 selected by default. Try a lower level if preserving fine detail is important, then compare the output's actual size and appearance. Re-run from the original if you change settings; no level guarantees a target size or a particular visual quality.
How much smaller will my PDF actually get?
The original image encoding, resolution and document structure affect the result. A PDF that is already optimised may offer little scope for reduction. Compare the input and output sizes directly and keep the original if the new file is larger without a useful improvement.
Does compression remove metadata, bookmarks or form fields?
Compression rewrites the internal structure of the file, so some embedded metadata or attachments can be dropped, and interactive elements such as forms or digital signatures are not guaranteed to survive. Treat the compressed file as a distribution copy: keep the original for archiving, and inspect the output if the document contains fields you still need.
Is it safe to compress confidential documents here?
This tool sends the document to the compression server. If your policy forbids that upload, use a local compression tool. The site's local Merge, Split and Rotate tools do not upload document contents, but they do not provide the same compression operation.
Why did my compressed PDF get bigger, or barely change?
A file that was already optimised — for example, one produced by a modern office suite or a previous compression pass — has little redundancy left, so re-encoding can occasionally add size instead of removing it. In that case keep the original. Recompressing the same file repeatedly also tends to degrade image quality without saving much space.
📖 Compress a PDF: Choose a Level and Check Size Against Quality →
Try the tools with sample files
Download sample files, compare page order, rotation and compression outputs, and understand processing limitations.
See checks and sample files →
