What's a reasonable PDF size for email?

Most email providers allow attachments up to 20-25MB, but for fast, reliable delivery across all recipients' email systems, aiming for under 10MB is a safer practical target.

Does compressing a PDF reduce text quality?

No, text in a PDF is typically stored as scalable vector data, not an image, so compression that targets embedded images doesn't affect text sharpness.

Why is my scanned PDF so much larger than a typed document?

Scanned pages are stored as images of the page, which are inherently larger than text-based PDFs where each character is just a small amount of structured data rather than a full image.

Can I reduce file size without any quality loss at all?

Some reduction techniques, like removing unused embedded fonts or unnecessary metadata, are lossless. But the biggest size reductions usually come from image recompression, which involves some quality tradeoff.

How to Reduce PDF File Size for Email Attachments

Why PDFs get large in the first place

Most email providers cap attachments somewhere between 20-25MB, and it's surprisingly easy for a PDF to exceed that without realizing why. The usual culprits, roughly in order of impact:

High-resolution embedded images — by far the most common cause. A handful of full-resolution photos embedded in a report can easily push a file past 20MB.
Scanned pages saved at unnecessarily high DPI — a scanner set to 600 DPI produces files several times larger than 200-300 DPI, with no visible quality difference for most text documents.
Embedded fonts — a PDF that embeds full font files (rather than referencing system fonts) adds size, though usually a smaller amount than images.
Many pages — simply having a lot of pages adds up, even if each one is individually small.

What actually shrinks a PDF

1. Recompress embedded images

This is usually the highest-impact fix. Images embedded in a PDF at print resolution (300 DPI or higher) are often far higher resolution than needed for on-screen viewing or even most printing. Reducing embedded image resolution and applying standard JPEG compression typically cuts file size dramatically with minimal visible quality loss.

2. Re-scan or re-export at a lower resolution

If you're the one creating the PDF from a scan, scanning at 200-300 DPI instead of 600 DPI for a text document will produce a much smaller file from the start, since text remains perfectly legible well below print-resolution settings.

3. Remove unnecessary pages or content

Sometimes the simplest fix is the right one — if your PDF includes pages that don't need to be in the version you're sending, removing them directly reduces size proportionally.

4. Split into multiple smaller files

If the document doesn't need to stay as a single file, splitting a large PDF into two or three smaller files (e.g., by chapter or section) and sending them separately, or via a cloud link instead of an attachment, sidesteps the size limit entirely.

What doesn't help much

It's worth knowing what generally has limited impact, so you don't waste time on it: removing metadata (author, creation date, etc.) saves a negligible amount in most cases, and simply re-saving a PDF without any actual recompression rarely changes file size meaningfully.

Actual attachment limits, for reference

Limits vary by provider, so it's worth checking the specific service you're using rather than assuming. Gmail's published help documentation states a maximum attachment size, and similar limits apply across other major email providers, generally in a comparable range. Keep in mind that some providers count the combined size of all attachments on a single email, not just the largest one, so three medium-sized PDFs attached together can hit the same limit as one large one.

When to use a cloud link instead of attaching the file

For files that remain large even after compression — long reports with many necessary high-resolution images, for instance — uploading to a cloud storage service and sharing a download link avoids attachment limits entirely, and also means you can update the file later without resending it.

Building a smaller PDF from the start

If you're creating a new PDF from images, you can control file size at the source by using reasonably-sized images. When using a tool like JPG to PDF to combine photos into a document, starting with moderately-sized images (rather than maximum camera resolution) keeps the resulting PDF email-friendly from the outset.