PDF Guide
How to Compress a PDF Online
A large PDF can be difficult to email, upload to a form, or store on a phone. Compression aims to reduce the file size while keeping the document readable. The amount saved depends on what the PDF contains: scanned pages and embedded images often offer more opportunities for reduction than documents made mostly of selectable text.
1. Check the file before compressing
Open the original PDF and confirm that its pages are complete, upright, and readable. If it contains forms or signatures, check whether those elements need to remain interactive after processing. Keep an untouched copy of important documents.
2. Run compression and compare the sizes
Use the PDF Compressor and save the processed file. Compare the original and output file sizes rather than assuming every PDF will shrink by the same percentage. A PDF that is already optimized may show little or no reduction.
3. Inspect the output quality
Open the new PDF and review pages with small text, diagrams, photographs, and tables. Confirm that links, page order, and any form fields important to your workflow still behave as expected. If the file becomes hard to read, use the original or try a less aggressive approach.
Other ways to reduce PDF size
- Resize oversized images before adding them to a document.
- When scanning paper, choose a resolution suitable for the intended use.
- Remove pages that are not needed, after checking the document carefully.
- Avoid repeatedly exporting and recompressing the same file, which can reduce image quality.
Privacy and sensitive documents
Before uploading any document to an online service, check how that service processes files. Do not use a tool for confidential or regulated documents unless its handling practices meet your requirements. Downloaded results should also be checked before submission.
When compression is not enough
If an upload has a strict size limit, verify the exact limit and accepted file type with the receiving website. You may also be able to split a large PDF into smaller files, provided the recipient accepts multiple documents.
Open PDF Split →