5 Ways to Shrink a PDF for Email Attachments
Email attachment limits are typically 10–25 MB. Five techniques — from quick browser tools to CLI commands — for getting PDFs under the limit.
Email attachments bounce when they're too large: Gmail caps at 25 MB, Outlook at 20 MB, many corporate servers at 10 MB. A high-resolution PDF from a designer or scanner can easily exceed these limits. Here are five techniques, from quickest to most thorough.
1. Use a Browser-Based PDF Compressor
The fastest option for a one-off file. A client-side tool requires no software install and no upload. For most scanned PDFs, you'll get a 50–80% size reduction in under 10 seconds. See our guide to choosing a safe file tool if you're sending sensitive documents.
2. Re-export from the Source Application
If you have the original file, re-exporting from the source is the cleanest approach — you're compressing from original data, not recompressing an already-compressed file.
- ●Word / PowerPoint: File → Save As → PDF → "Minimum size (publishing online)"
- ●Google Docs: File → Download → PDF (Google applies automatic optimisation)
- ●InDesign: Export PDF → Compression → Downsample images to 150 DPI
- ●macOS: Print → PDF → Quartz Filter → "Reduce File Size"
3. Ghostscript (Free, Maximum Control)
# /ebook — 150 DPI, good quality, typical 60-70% reduction
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.5 \
-dPDFSETTINGS=/ebook -dNOPAUSE -dQUIET -dBATCH \
-sOutputFile=compressed.pdf input.pdf
# /screen — 72 DPI, maximum compression for email
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.5 \
-dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH \
-sOutputFile=compressed.pdf input.pdf4. Remove Hidden Elements
Large PDFs often contain hidden layers, attached files, form field data, or embedded colour profiles that add size without visible content:
# qpdf — strip restrictions, flatten annotations, linearise
qpdf --linearize --remove-restrictions input.pdf output.pdf
# ExifTool — remove all PDF metadata
exiftool -all= -overwrite_original input.pdf5. Share a Cloud Drive Link Instead
When compression isn't enough — large architectural drawings, high-resolution portfolios, multi-section reports — bypass attachment limits entirely. Upload to Google Drive, Dropbox, or OneDrive and share a link. This works for files up to several GB and preserves full quality.
Regularly sending PDFs over 5 MB by email is worth questioning. A shared folder workflow often serves the collaboration better and preserves full quality on both ends.
For most situations, a quick pass through our PDF compressor will get any file under a standard email limit in seconds.
Ready to try it?
All tools run entirely in your browser — no uploads, no account required.
Compress PDF