PDF too large to email? Five fixes, ranked

First, know the limit you actually hit

Providers publish different numbers, and the number that stops you is the smaller of the sender's limit and the recipient's. A message that leaves Gmail happily can still bounce off a corporate server configured at 10 MB.

Attachments are re-encoded for transport, which inflates them by roughly a third. A 20 MB file can arrive at the server as about 27 MB — which is why a 24 MB file gets rejected by a 25 MB limit.

1. Compress it — fixes most cases

Start here, because it is one step and usually enough. Scanned documents routinely fall by 50–90%, which turns a blocked 30 MB attachment into a 4 MB one that sends instantly.

Use the Recommended level first. It keeps printed text sharp while removing the redundant image data that makes scans heavy. Only reach for Extreme if you are still over the limit afterwards.

If the file barely shrinks, that tells you something useful: it was already efficient, and the weight is real content rather than waste. Move on to fix 4 or 5.

2. Convert to grayscale — free extra savings

If the document is text on white paper, the colour information is doing nothing for you. A colour scan stores three channels per pixel where one would do.

Converting to grayscale removes the other two, shrinking the file further and making scans look cleaner and more consistent in the process — the faint blue or yellow cast that scanners add to white paper disappears with it.

Do this before compressing, not after. The two steps together typically beat either one alone.

3. Delete the blank pages

Double-sided scanners capture the back of every sheet, so single-sided documents come out with an empty page between each real one. Those blanks are full-size images of nothing — complete with the faint speckle every scanner produces — and on a long scan they can be half the file.

Removing them is instant, lossless and often more effective than compression. A 60-page scan that is really 30 pages plus 30 blanks loses about half its size the moment the blanks go.

4. Split it and send what matters

Nobody wants an eighty-page report when six pages are relevant. Splitting by page range solves the size problem and is genuinely more considerate to the person reading it.

It also sidesteps limits entirely if you send two smaller messages — though check with the recipient first, since some filing systems dislike documents arriving in pieces.

5. Share a link instead

When the file is genuinely large — high-resolution artwork, a photo book, an architectural drawing set — compression is the wrong tool. There is no redundant data to remove; the size is the content.

Upload it to your own cloud storage and send a link. Just remember that this is the one option on this list that does put your document on someone else's server, so it is the wrong choice for anything confidential.

A worked example

A 42 MB scanned contract, blocked by a 10 MB corporate limit. Here is the order that gets it through, and what each step buys you:

1. 1Delete blank pages: 60 pages become 31. Now 22 MB.
2. 2Convert to grayscale: the colour channels go. Now 14 MB.
3. 3Compress at Recommended: the image data is optimised. Now 3.1 MB.
4. 4Send it. Total time: under a minute, and the text is still sharp.

Notice that compression was the last step, not the first. Removing content you do not need before compressing what remains is always more effective than compressing everything.

What not to bother with

Zipping a PDF saves almost nothing. PDFs are already compressed internally, so a ZIP typically shaves off 1–3% while making the file more annoying for the recipient to open.

Printing to PDF again at a lower quality setting can help, but it is unpredictable and often strips the text layer, leaving you with an unsearchable document. Use a compression tool that targets the images specifically.

Screenshotting each page is the worst option of all: it multiplies the file size, destroys the text layer and produces something nobody can search or copy from.