Why PDFs Get So Large
PDFs balloon in size due to: high-resolution embedded images, multiple fonts, uncompressed layers from design tools (InDesign, Illustrator), and embedded colour profiles. One scanned photo at 600 DPI can alone make a PDF several megabytes.
Method 1: Re-export From the Source
If you created the PDF from Word, PowerPoint, or a design tool, re-export it using the "Optimised PDF" or "Web" preset. This alone usually cuts 40–60% of file size.
Method 2: Use an Online Compressor
Tools like ILovePDF (online) and PDF24 (free, no limits, no watermarks) offer free PDF compression. ILovePDF compresses using Ghostscript and is effective for image-heavy PDFs.
Method 3: Image → PDF workflow
Extract the PDF pages as images, compress the images, then re-merge. More steps but gives you the most control over the final quality. Use FreeMediaKit's PDF Converter for both the extraction and re-merging steps.
Target Sizes
- Email attachment: under 10 MB (most email servers cap at 25 MB)
- Web embed: under 5 MB for fast loading
- Print: size doesn't matter — prioritise quality