Compress PDF File
Reduce the file size of a PDF without losing quality.
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Maximum file size: 20MB
How to Compress a PDF
- Upload the PDF you want to shrink.
- Pick a compression level based on how the file will be used.
- Download the compressed PDF.
- Open it and check that the quality is still acceptable for your purpose.
Which Level to Choose
- High quality keeps images close to the original and saves the least space. Use it for documents you intend to print.
- Balanced is the default and targets on-screen reading, which suits most email and upload situations.
- Maximum compression produces the smallest file by reducing image detail more aggressively. Use it when a strict size limit matters more than fidelity.
How Much Smaller Will the File Get?
Most of the size in a large PDF is usually images. Compression works by storing those images at a lower resolution or with stronger encoding, so a scanned or photo-heavy document can shrink dramatically.
A PDF that is mostly text is a different story. Text takes very little space to begin with, so there is little to remove and the saving may be small. In some cases a file that has already been optimised will barely change at all. There is no guaranteed reduction, and any tool claiming otherwise is overpromising.
Limits
- One PDF per operation.
- Requests are rate limited to ten per minute from the same address.
- Only PDF input is accepted.
Common Use Cases
- Getting a document under an email attachment limit.
- Meeting the maximum upload size on a government or exam portal.
- Reducing a scanned document before archiving it.
- Making a file quicker to send over a slow connection.
Limitations
Compression is not lossless at the lower quality settings. Images are re-encoded, so fine detail can soften, and pushing to maximum compression on a scan can make small print harder to read. Always check the output before discarding your original.
If the server has to fall back to a secondary method, the whole page may be rasterised, which reduces text sharpness. In that case the response includes a warning so you know the quality was affected.
Privacy and Processing
Compression happens on our server, so the PDF is uploaded. It is used only to produce your compressed download, which is removed after it is sent, and temporary files are cleared automatically.
Compress PDF File FAQ
How much smaller will my PDF get?
It depends entirely on the content. Scanned or image-heavy documents can shrink dramatically because images hold most of the size. A text-only PDF may barely change, because there is little to remove. No compression tool can guarantee a fixed reduction.
Which compression level should I choose?
Use high quality for documents you will print, the balanced setting for on-screen reading and most email or upload situations, and maximum compression only when a strict size limit matters more than image fidelity.
Does compression reduce quality?
Yes, at the lower settings. Images are re-encoded at reduced detail, so fine detail can soften and small print in a scan can become harder to read. Always check the result before deleting your original.
Why did my file barely change?
Either the PDF is mostly text, which is already compact, or it has already been optimised. In both cases there is very little redundant data left to remove.
Is the text still selectable after compression?
Normally yes. If the server has to fall back to a secondary method the pages may be rasterised, which affects text sharpness; in that case the response includes a warning so you know quality was affected.
Is my file uploaded?
Yes. Compression happens on our server, so the PDF is uploaded. It is used only to produce your download, which is removed after it is sent, and temporary files are cleared automatically.
Related Developer Tools
Keep moving through common developer workflows with Merge PDF, Split PDF, PDF to Image. You can also browse the full Developer Tools collection or return to the all tools hub.