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Home/Compress/Email limits

Get a PDF under the attachment limit

The message bounces and the number in the error is the only guidance you get. Before shrinking anything, it’s worth knowing how much has to go, and whether the thing making the file large is even the part you care about.

Drop the PDF you want to compress

or choose a file

Even dozens or hundreds of pages are fine. It's handled one page at a time, so the page never locks up

Work out the budget first

Your provider’s limit isn’t the limit that matters. A 25 MB attachment limit is common, but the recipient’s mailbox quota, their spam filter and any gateway in between can refuse something well under it. Twenty megabytes is the figure that clears almost everything.

Attachments are also base64-encoded in transit, which inflates them by roughly a third. A 20 MB file can present as closer to 27 MB to a gateway enforcing a cap on the encoded size, which is why a file that sits comfortably under the stated limit still bounces.

The practical target. Aim for under 20 MB if the file has to arrive by email, and under 10 MB if it will be forwarded on. Every hop re-checks the size, and the smallest limit in the chain is the one that decides.

Find out what is making it large

Run the file through and read the two numbers before choosing a setting. Size divided by page count tells you what you’re dealing with.

A few hundred kilobytes per page is normal for real text. A few megabytes per page means images, which means the image route has something to work with. If the file doesn’t look large enough to need this at all, check what’s actually in it. A logo pasted at full camera resolution, or one scanned page inside an otherwise digital document, is a common culprit.

Under 100 KB per page
Born-digital text. Compression will barely move it; the lossless route is all that helps, and only slightly.
100–500 KB per page
Text with a few images. Mixed results, and the tool picks whichever route wins.
Over 1 MB per page
Scanned or image-heavy. This is where the 80–95% reductions live, and where the setting you choose matters.
One huge page among small ones
Usually a full-resolution image inserted into a text document. The result panel reports the overall change, not per-page.

The setting to pick for email

Email is the least demanding destination a PDF ever has. It’s read on a screen, usually at 100%, and printed at most once. That makes the balanced setting almost always right, and the aggressive ones a common mistake.

The exception is a file something will read mechanically at the far end: a form, a statement feeding an automated check, anything with a barcode. Those want the lossless route or a high resolution, because the software reading them has no human to fill in the gaps.

Don’t compress a file to make something unreadable smaller. Compression changes how pages are stored, not what is on them. An account number that goes out compressed is still an account number. If the problem is content rather than size, redact is the tool, and it should run first, since redaction costs file size rather than saving it.

When it still won’t fit

If the smallest honest output is still over the limit, size isn’t the problem to solve. These work, in the order worth trying.

Send fewer pages. A twenty-page statement cut to the three pages the recipient asked about is smaller than any compression can achieve, and it’s a better document to send.

  • Split the document and send the parts as separate attachments, or across two messages.
  • Extract just the pages in question, since organize can pull a range into its own file.
  • Send a link instead. A file on your own storage, or a service the recipient already uses, skips every size limit in the chain.
  • Ask whether they accept a shared folder. For a document this size, that’s usually the channel they expected anyway.

Straight answers

What is the actual email attachment limit?

Commonly 25 MB, sometimes 20 or 10. The one that matters is the lowest limit anywhere between you and the recipient, and you can’t see most of those. Aim well under and you stop having to care.

Why did a 19 MB file bounce on a 25 MB limit?

Because it’s base64-encoded in transit, which adds about a third to its size on the wire. A gateway checking the encoded size sees roughly 25 MB, not 19.

The balanced setting made it blurry. What now?

Go up rather than down. Faithful at 200 dpi is the setting for anything someone will read closely, and on a scan it’s usually still a large reduction, just a smaller one than the aggressive settings promise.

Will compressing it break the links and bookmarks?

Only if the image route wins. Ticking Keep the editable structure skips that route entirely, keeping links, bookmarks, form fields and the text layer, at the cost of a much smaller reduction.

Can I compress several files at once?

Not in one pass. If several documents are going to the same person, merge them first and compress the result. One attachment under the limit is easier to send than four that each need their own check.

More on compress

Compress a bank statement PDF before you upload it

Mortgage portals, visa applications and expense systems usually cap an upload at 2–5 MB, and a year of statements is often more than that.

Compress a scanned PDF

This is the case compression was built for.

The full tool, with every option: Compress.