Compress a PDF: Choose a Level and Check Size Against Quality
A smaller PDF is useful only if the recipient can still read it. Before opening Compress PDF, note the actual upload limit and keep a copy of the original. The tool has levels 1–9; it does not offer an exact target-size field.
Compression is a server-processing tool. Selecting a file prepares it in the page; pressing Run sends the PDF for processing. Review the privacy information and your document-handling requirements before using it.
Start with level 5, then compare
- Open Compress PDF and choose a PDF.
- Leave Compression level at the default 5 for a first comparison.
- Select Run and wait for the download. A completed request shows a check mark and the output filename.
- Compare the original and output file sizes in your device’s file manager. Open the downloaded PDF in a reader; the tool does not provide a side-by-side quality preview.
- If the result is still above the upload limit, try a higher level using the original file. If fine detail has become unclear, try a lower level instead.
Level 1 is labelled light and level 9 maximum. The same level does not yield the same size reduction for every document. Stop increasing compression when it makes required text or images hard to read.
A documented image-PDF example
You can download the input and recorded output without using your own documents:
| Item | File and recorded size |
|---|---|
| Input | image.pdf, 988,505 bytes |
| Setting | Compression level 5 |
| Recorded output | compressed-level-5.pdf, 88,005 bytes |
| Recorded check | One readable PDF page |
These values come from the September 13, 2026 check record, which used the site’s compression service. This synthetic image example is one measured result, not a prediction for contracts, scans or other PDFs. A later run may also produce different bytes as processing software changes.
To repeat the exercise, load the input, select 5 and run it. Compare page count, visible image detail and file size with the saved output. Do not use matching file size alone as proof of a good result.
What to inspect before submitting
Check small print and punctuation at a useful zoom, not just a fit-to-page thumbnail. Inspect signatures, stamps, thin lines, diagrams and any barcode or QR code the recipient needs to read. Confirm that no page is missing or blank. If the original had searchable text, try searching for a phrase in the output too.
Existing certificate signatures and interactive forms need separate validation. Compression rewrites the PDF; a visually similar page does not prove those features remain usable.
When the file stays large or the request fails
A PDF containing mostly text or already-compressed images may have little room to shrink, and an output can even be larger. Keep the smaller acceptable version rather than assuming every run improves it.
If only some pages are required, extract those pages before compressing. If all pages are needed but quality suffers, re-export from the source document at an appropriate image resolution, or ask the recipient whether separate files are accepted.
For a server or connection error, try the public sample to distinguish a service problem from a document-specific problem. Keep the original and the error message. There is no guaranteed processing time or unlimited-size promise for this service.
FAQ
Can I guarantee a PDF will be below 2 MB?
No. The tool offers compression levels, not a guaranteed target size. Check the downloaded file against the recipient's limit; already-compressed or mostly text files may shrink very little.
Does compression happen on my device?
No. Compress PDF sends the selected PDF to the processing server when you run it. Read the privacy information and use documents you are permitted to send for processing.
Should I compress the compressed copy again?
When comparing levels, start from the original PDF each time. Repeated processing can compound quality loss and makes it harder to compare settings.