Compress PDF
Reduce PDF file size with lossless optimisation that keeps text and images unchanged. Runs in your browser, so your files are never uploaded.
Compress PDF
Reduce PDF file size without losing quality
100% Secure
Files processed locally
Fast
Instant compression
Unlimited
No limits
About Compress PDF
Compress PDF re-saves your document with an optimised internal structure, which can make some files smaller without touching the visible content. It works best on PDFs that were produced by software that writes bulky, uncompressed object data, and it is a quick first step when a file is just over an upload or email size limit.
It is important to be realistic about what it does. The tool does not downsample photographs or re-encode scanned images, so a PDF that is large because it contains big images will shrink only a little. The tool shows the original and compressed sizes so you can see the actual result for your file before deciding whether to use it.
How to use the Compress PDF
- Click the upload area and select your PDF.
- Click Compress. The file is processed locally and the optimised copy downloads as yourfile_compressed.pdf.
- Compare the Original Size and Compressed Size figures shown on the page.
- If the saving is small and you need a smaller file, see the tips below for image-heavy documents.
What it can do
Structure optimisation
Uses object streams to store the document structure more compactly.
Content untouched
Text, images and layout are not altered, so there is no visible quality change.
Size comparison
See exact before and after sizes so you know whether it helped.
Runs locally
Your PDF is processed in your browser and is not uploaded.
When it is useful
- Getting a document under an email attachment limit when it is only slightly too large.
- Tidying PDFs exported from some office and reporting tools that write verbose internal data.
- Reducing storage for a folder of text-based documents.
Good to know
- Scanned documents and PDFs full of photos contain large images. Results on those files can be minimal because images are not recompressed by this tool.
- If a file does not shrink, the original may already be optimised. In that case, keep the original.
- For image-heavy PDFs, a better route is to reduce the images before building the PDF, for example with the Image Compressor, or to re-export the document from its source application at a lower image quality.
Read the guide: Compress PDF Tool Guide
Related tools: Merge PDF, Split PDF, Image Compressor, PDF to Image