Example: a scan exceeds an attachment limit
A scanned application is too large to attach. Start with Best Quality and compare the size shown after processing with the upload limit. If it is still too large, try Balanced only if some image quality loss is acceptable. Check small print, stamps, and signatures in the downloaded copy before sending it.
What lossless PDF compression means
Lossless compression stores the same PDF data more efficiently. Best Quality recompresses supported data streams and uses compact object storage. It does not resize images, convert whole pages to pictures, or reduce image quality. Selectable text and vector graphics remain in the PDF.
This tool does not promise a percentage reduction. Many PDFs already contain compact JPEG images and compressed streams. Rewriting those files can produce little or no savings. If the generated file is not smaller, the tool offers the unchanged original.
Compress a PDF step by step
- Open Compress PDF and choose a PDF up to 100 MB from your device.
- Keep Best Quality selected for lossless compression.
- Select Compress PDF and wait while the browser optimizes the document.
- Compare Original size, Download size, and Saved. An already optimized result means the original file was kept.
- Download and open the result. Review its pages before sharing.
Choose an optional image compression mode
Balanced uses higher-quality JPEG encoding and caps large eligible images at 2,400 pixels along their longest edge. Maximum Compression uses stronger JPEG compression and a 1,400-pixel cap. Neither mode enlarges small images. Both can soften detail, especially small text inside a scanned page.
These modes optimize supported RGB or grayscale images. Images with masks, custom color spaces, predictors, or other unsupported settings are preserved. Text and vector elements remain intact. There is no automatic switch from lossless to a lossy mode.
Why a file may still be too large
There is no guaranteed target size, such as 200 KB or 1 MB. A long scan may remain large even after image compression. Remove pages you do not need or extract the required section using the related tools, then check whether the recipient accepts that smaller document.
Processing stays in your browser. Large or complex PDFs can exceed your device memory. Try a smaller document if processing fails. Password-protected PDFs need an unlocked copy you are authorized to use. Digitally signed PDFs are rejected because compression would invalidate their signatures.
Check quality before sending
- Review the first and last page and confirm the page count.
- Zoom into small text, diagrams, stamps, and scanned handwriting.
- Check selectable text, links, and form fields when they matter. Keep the original document.
- Use Best Quality for documents where original image detail matters.
Put the guide into practice
Start with a copy of your document and check the result before sharing it.
Use Compress PDF