How to Make a PDF Small Enough to Email

Where the size comes from

A PDF of pure text is tiny. A fifty-page contract is often under a megabyte. If your file is large, something else is inside it, and it is almost always one of three things.

• Scanned pages. A scanner produces one photograph per page. At 600 dpi in colour, a single A4 page can exceed 5 MB on its own.
• Embedded photographs at full camera resolution. A picture that occupies a quarter of a page is often stored at the full resolution it came off the camera, twenty times more data than the page can display.
• Embedded fonts. Usually modest, but a document using several full font families adds up, particularly with fonts covering many languages.

Knowing which one applies decides which fix will help. Compressing a text-only PDF achieves almost nothing, because there is nothing to compress.

Fix one: send fewer pages

The most reliable reduction is not compression at all. If the recipient needs three pages of a ninety-page report, send three pages. This is instant, loses nothing, and often takes the file from unsendable to trivial.

You can pull out a page range with the split PDF tool, which extracts the pages you choose into a new file in your browser. It is worth trying before anything else, simply because it cannot degrade quality.

Fix two: shrink the images before they go in

If you are the one building the PDF, this is where the real saving lives. An image placed into a document at 4000 pixels wide, displayed at 800 pixels, contributes twenty-five times more data than the page needs.

Resize your images before assembling the document — the image resizer does this — and then compress them with the image compressor. A photo-heavy PDF built from prepared images is routinely a tenth the size of the same document built from camera originals, with no visible difference on screen.

If you are building a PDF from photographs directly, the images to PDF tool lets you set the page size, which caps how much resolution each picture contributes.

Fix three: rescan at a sensible resolution

Scanner defaults are frequently far above what the job needs. For a document that will be read rather than reprinted at high quality, 200 to 300 dpi is sufficient, and greyscale rather than colour halves the size again for anything that is not colour-critical. Many scanners also offer a "text" or "document" mode that applies compression tuned for pages of writing.

Rescanning feels like extra work, but it produces a far better result than compressing a bloated scan afterwards, because you avoid the damage rather than trying to hide it.

Fix four: split the file and send it in parts

When the whole document genuinely must be delivered and it will not shrink enough, dividing it is the honest solution. Split it into two or three files and send them as separate emails. Recipients can reassemble the parts if they need to, using a merge PDF tool.

Fix five: do not attach it at all

Above roughly 20 MB, a link is a better delivery mechanism than an attachment regardless of whether the file would technically squeeze under the limit. Cloud storage links do not bounce, do not sit in the recipient's mailbox quota, and let you replace the file if you find a mistake.

The order to try things

1. Remove pages the recipient does not need.
2. If you built the document, rebuild it from resized images.
3. If it is a scan, rescan at 200–300 dpi in greyscale.
4. Split it and send it in parts.
5. Send a link instead of an attachment.

Each step earlier in that list preserves more of the document than the one after it.

Frequently asked questions