Practical guide
How to use Compress PDF well
Compress PDF reduces the storage size of a PDF so it is easier to email, upload or archive. You can choose high, medium or low quality. Compression may optimise the document structure and resample embedded images; it does not guarantee a particular final size because every PDF contains a different mix of text, fonts and images.
How to use this tool
- Upload one PDF and choose a quality preset.
- Use high quality for documents that must stay visually close to the original, medium for general sharing, or low when smaller size matters most.
- Compress the file, compare the downloaded result with the original and check small text, diagrams and photographs.
Common uses
- Bring an attachment under an email or application portal limit.
- Reduce image-heavy scans before sharing them.
- Save space when archiving copies of non-master documents.
- Make a PDF faster to transfer over a mobile connection.
Privacy and document handling
The file is processed temporarily on the PDFTools server. PDFTools removes uploaded inputs after the job and provides an expiring output link rather than permanent cloud storage. Document contents are not used to personalise advertisements. The displayed filename and operational status may remain briefly in logs without retaining the document itself.
Important limitations
Text-only PDFs may already be compact and show little reduction. Image-heavy files usually offer more savings, but aggressive compression can soften photographs, charts and scanned text. Compression does not remove passwords, redact information or guarantee that hidden metadata disappears. Keep the original master file until you have reviewed the result.
Frequently asked questions
Which quality should I choose?
Start with medium. Move to high if details look soft, or low if a strict upload limit matters more than image quality.
Why is my result not much smaller?
The source may already be compressed or consist mainly of efficient text and vector graphics.
Does compression change page dimensions?
No. The page size and order should remain the same.
Can compression repair a damaged PDF?
No. Use Repair PDF for structural damage; compression is intended for readable files.
Related PDF tools
Guide reviewed by the PDFTools team · Updated 16 August 2026