What is the email attachment size limit?

It varies by provider, but many cap attachments around 20–25 MB. If your PDF is larger, the email will be rejected, so you need to shrink the file or share it another way.

What is the fastest way to make a PDF smaller for email?

Run it through a compression tool at the Recommended level. For most documents this cuts size by 40–70% with no visible quality loss — usually enough to get under the limit.

Why is my PDF so large in the first place?

Almost always because of images — high-resolution scans and embedded photos. Text takes very little space, so a short scanned document can be far larger than a long text-only one.

What if compression is not enough?

Split the PDF and send only the pages that matter, or OCR a scanned file first so it compresses better. As a last resort, share via a cloud link instead of attaching.

PDF Optimization

PDF Too Big to Email? 7 Ways to Shrink It Fast (2026)

By The OptaPDF Team • Published June 17, 2026 • 6 min read

Few things are as annoying as hitting "send" and getting bounced because your PDF is too big. Most email services cap attachments around 20–25 MB. The good news: almost any oversized PDF can be slimmed down in a minute. Here are seven free ways, from easiest to most thorough.

1. Compress it (start here)

Ninety percent of the time, this alone solves it. Open Compress PDF, choose the Recommended level, and you will typically cut 40–70% of the size with no visible quality loss. The result screen shows the exact savings before you download.

2. Use a higher compression level

Still over the limit? Re-run the original at the Extreme level. It softens images more aggressively but is perfect when you must hit a strict cap. Always start from the original file, not an already-compressed copy.

3. Send only the pages you need

Does the recipient really need all 60 pages? Use Extract Pages or Split PDF to pull out just the relevant section. A 5-page extract is a fraction of the size of the full document.

4. OCR scanned documents first

Scans are the biggest offenders. Running a scan through OCR PDF adds a text layer and often makes the file compress far more efficiently afterward — a useful one-two punch with compression.

5. Split a big file into parts

If the whole document genuinely needs to go, use Split PDF to break it into two or three smaller PDFs and send them across separate emails, each under the limit.

6. Remove heavy extras

Large embedded images or full-resolution photos pasted into the document add weight. Compression handles most of this automatically, but trimming unnecessary image-heavy pages before compressing helps even more.

7. Share a link instead

When a file is simply too large to attach, upload it to a cloud service and email the link. It is the most reliable way to deliver very large documents without attachment limits.

Quick decision guide

Situation	Best fix
Slightly over the limit	Compress (Recommended)
Well over the limit	Compress (Extreme) or split
Only part is needed	Extract Pages
It is a scan	OCR then compress

Summary

Start with compression at the Recommended level — it usually does the trick. If not, send fewer pages, OCR scans before compressing, or split the file. One of these seven will get your PDF under the limit and on its way.