What is PDF Compression?
PDF compression reduces a PDF file's size — often by 70 to 90 percent — by re-encoding the images inside it at lower resolution, removing duplicate embedded fonts and stripping hidden data. A 25 MB scanned document can typically shrink to 2 or 3 MB while remaining perfectly readable, because scans are usually stored at far higher quality than screens or portals need.
The everyday Indian trigger is a government or bank portal rejecting an upload: "file must be under 1 MB" for a scanned Aadhaar, marksheet or property paper. Online compression tools fix this in seconds without installing software. Businesses also compress catalogues and quotations before WhatsApp or email delivery — a 2 MB brochure opens instantly on a customer's phone, while a 40 MB one often never gets downloaded.