Compress PDF for Email — Get Under Gmail and Outlook Size Limits Free
Gmail has a 25 MB limit, Outlook 20 MB. Here is how to compress scanned PDFs to 3-5 MB without visible quality loss, entirely in your browser.
Gmail blocks attachments over 25 MB. Outlook defaults to 20 MB. A scanned PDF of a ten-page document can easily hit 15-20 MB at scanner defaults. Compressing to under 10 MB solves the problem without switching to file transfer services.
Why scanned PDFs are large
A scanned page is a high-resolution raster image embedded in a PDF container. At 300 DPI, a single A4 page is about 2480 x 3508 pixels, and at default scanner quality that is 1-3 MB per page. Ten pages can easily reach 15-25 MB before any optimization.
Native PDFs from Word or Excel are much smaller because they contain vector text and shapes rather than pixel images. Compressing a native PDF typically saves 30-60%. Compressing a scanned PDF saves 70-85%, because most of the size is unoptimized image data.
How to compress for email
- Open the PDF Compressor.
- Upload your PDF and try Auto preset first.
- Download and check the file size.
- If still over limit, re-upload and try eBook (150 DPI) or Screen (72 DPI).
Preset guide
- Auto: Good starting point. 150 DPI images, font subsetting.
- eBook (150 DPI): Best for email sharing. Readable on any screen.
- Screen (72 DPI): Maximum compression for screen-only reading.
- Printer (300 DPI): When the recipient needs to print clearly.