3 Ways to Reduce PDF File Size
How do you shrink a PDF's file size while preserving quality to get past email limits?
Why do PDFs get big?
The thing that inflates a PDF's size the most is images. High-resolution scanned pages or embedded photos can quickly push a file into tens of megabytes.
The second big factor is embedded fonts and unnecessary metadata. Most email attachments hit the 25 MB limit — which is why compression often becomes mandatory.
Way 1: Metadata and structure optimization
The lightest method is cleaning up the unnecessary data inside the file: unused objects, old version info, redundant metadata.
The 'Balanced' mode in FluoPDF's 'Compress' tool does exactly that — with object stream optimization and metadata cleanup it saves size without touching image quality.
Way 2: Resampling images
If your PDF contains scanned pages, the real gains come from lowering the resolution of the images. A 600 DPI scan can be reduced to 150 DPI for on-screen reading.
This method can shrink the file by 70-90% but affects image quality. Use it carefully for documents you'll keep for printing.
Way 3: Remove unnecessary pages
Sometimes the simplest solution gets overlooked: are there pages in the document you don't actually need? Blank pages, cover images, repeated appendices...
With FluoPDF's 'Extract Pages' tool you can move only the pages you need into a new PDF and lower the file size naturally.
Which method, when?
If you're over the email limit by a few MB, metadata optimization is enough. For a thick scanned document, image resampling is a must.
The ideal approach: first remove unnecessary pages, then compress. Combining the two methods keeps both size and quality in the best balance.