"The attachment size exceeds the allowed limit." Few messages are as annoying when you're trying to send an important document. Email providers cap attachments — Gmail and Outlook at 25 MB, many corporate servers at 10 MB, and some older systems at just 5 MB. The good news: almost any oversized PDF can be brought under these limits in a minute, without printing, paying, or losing readable quality.
The fastest fix: compress it
- Open Compress PDF.
- Drop in your file.
- Click Compress PDF and download the smaller version.
It runs in your browser, so even a confidential document is never uploaded. For most files — especially scans — this single step is enough to clear a 25 MB or 10 MB limit.
Know your target
Different systems have different caps. Aim a little below the limit to leave room for the email itself:
- Gmail / Outlook.com: 25 MB — target ~20 MB
- Many company mail servers: 10 MB — target ~8 MB
- Older or strict systems: 5 MB — target ~4 MB
If you don't know the recipient's limit, under 10 MB is a safe bet for almost everyone.
Still too big? Work down the list
If one pass of compression doesn't get you there, apply these in order — each one removes more weight:
- Remove pages you don't need. Blank pages, duplicates and cover sheets add up. Drop them with Remove Pages, then compress again.
- Send only the relevant pages. If the recipient needs pages 3–7, don't send all 40. Pull just those with Extract Pages.
- Split the document. For a genuinely large file that must stay whole, break it into parts with Split PDF and send them as separate emails.
- Export heavy scans as images. If you only need the pictures, PDF to JPG can be far smaller than the full PDF.
Why is my PDF so big in the first place?
Understanding the cause helps you fix it faster:
- High-resolution scans are the usual culprit — a single 600 DPI page can weigh several megabytes. For on-screen reading, 150 DPI is plenty.
- Embedded fonts add weight so the file renders identically everywhere.
- Re-exported files accumulate redundant data and metadata each time they're saved.
Compression targets exactly this waste, which is why it works so well without changing how your document looks.
What about quality?
With sensible compression, text stays sharp and images stay clear — the tool trims redundant data and right-sizes oversized images rather than degrading everything. You'd only notice a difference if you compressed an image-heavy file very aggressively. If you need pristine fidelity for professional printing or a legal filing, keep the original and only email a compressed copy. There's a fuller explanation in our guide on compressing without losing quality.
Alternatives to attaching at all
If a file simply won't shrink enough — or you'd rather not email sensitive documents — consider a secure link from a cloud service instead, and password-protect the PDF first with Protect PDF so only the intended recipient can open it.
Frequently asked questions
How do I get a PDF under 25 MB? One pass through Compress PDF clears the 25 MB Gmail/Outlook limit for the vast majority of files.
How do I get it under 5 MB? Compress it, then remove or extract only the pages you actually need. For very large scans, splitting the file is the reliable option.
Will compressing ruin the quality? No — with normal settings, text and images stay clear. Only extreme settings on scan-heavy files become visible.
Are my files uploaded? No. Compression happens in your browser, so your document never leaves your device.
Get your file under the limit now: Compress PDF →