Compress PDF
Reduce PDF file size with lossless optimization or stronger image-based compression modes, entirely in your browser.
Turn this result into a calculation record
Carry the tool context into the PROFENG calculation-check and record workspace without implying certification or engineering approval.
Formula source and acknowledgement
Source being confirmed. PROFENG has not yet approved a published source for this exact calculator implementation, so no candidate book, paper or standard title is displayed here.
Credit for any underlying published method belongs to its original author(s) or standards body. PROFENG presents its own implementation and wording and does not imply endorsement or affiliation.
Read the PROFENG methodology for formula sourcing and automated checks →
Why use this compress pdf?
Compress PDF helps reduce PDF file size before email, upload or storage. Lossless mode rewrites the PDF structure while preserving selectable text and vector content; Balanced and Smallest File modes rebuild pages as compressed images for stronger reductions on scanned or image-heavy documents.
Example
Upload a scanned 12 MB PDF, choose Balanced mode and compare the resulting size before downloading. If the document contains important searchable text or vector drawings, try Lossless first.
Important note
Strong compression is a trade-off. Balanced and Smallest File rasterize each page, so text is no longer selectable/searchable and fine print or drawings can lose quality. Keep the original PDF until you have reviewed the compressed copy.
How to use it
Start with the inputs shown above, review the assumptions or options, then generate the result. Where the tool creates a file, keep the original until you have opened and checked the downloaded output.
Frequently asked questions
Is Compress PDF free?
Yes. The core tool is free to use without creating an account.
Do I need an account to use Compress PDF?
No. You can use the core Toolbox workflow without signing up.
Does Compress PDF work on mobile?
Yes. Toolbox is designed for modern mobile and desktop browsers, although complex file workflows can be easier on a larger screen.
QA, changelog and corrections
Last QA update: 30 September 2026.
This page is covered by publication and metadata QA only unless a tool-specific automated verification status is displayed above. No named-expert review is claimed.
Changelog
30 September 2026 – source/indexation status, metadata and correction pathway reviewed. Engineering tools display the automated verification label only when they are inside the passing Part 3 verification scope.