Most email providers limit attachments to between 10MB and 25MB. If you've ever tried to email a PDF scan, a brochure, or a presentation and hit that limit, you know how frustrating it can be. Here are the most effective ways to reduce PDF file size.
Why Are Some PDFs So Large?
PDF file size depends on what's inside. The main culprits are:
- High-resolution images — photos embedded at print quality (300 DPI) are much larger than needed for screen viewing
- Scanned pages — scanning creates large image files for each page
- Embedded fonts — some PDFs embed complete font files
- Unnecessary metadata — comments, revision history, and hidden layers add bloat
Method 1: Use a PDF Compressor
The fastest approach is an online PDF compressor. PDF24x's compression tool reduces file size by optimising images and removing unnecessary data. Upload your PDF, choose a compression level, and download the smaller version.
For most documents, Medium compression reduces file size by 40-60% with no visible quality loss. For image-heavy files, Strong compression can achieve 70-80% reduction.
Method 2: Reduce Image Resolution Before Creating the PDF
If you're creating a PDF from images, resize them to 150 DPI before converting. Screen resolution is 72-96 DPI, so 150 DPI is more than enough for digital documents and significantly smaller than 300 DPI print quality.
Method 3: Split the PDF
If the document is long and you only need to send certain pages, use a PDF splitter to extract just the relevant pages. A 50-page report becomes much smaller when you only send the 5 pages the recipient actually needs.
Method 4: Use a Cloud Link Instead
For very large files, upload the PDF to Google Drive, Dropbox, or OneDrive and share a link instead of attaching the file. This bypasses email size limits entirely and the recipient can preview it in their browser without downloading.
What Compression Level Should You Choose?
- Low compression — minimal quality loss, 20-30% size reduction. Good for important documents where quality matters.
- Medium compression — balanced quality and size. Best for most emails.
- High compression — significant size reduction, some quality loss. Fine for draft documents or internal use.
Ready to compress your PDF? Use the PDF24X compressor — free, no sign-up. Also see: How to compress a PDF without losing quality.