Does compression damage the document?

Low is lossless — text remains selectable and crisp. Medium and High rasterise pages to JPEG, which makes text non-selectable but still readable. For a signed contract you want to keep editable, stick to Low.

How do I get under 5 MB?

If 'High' isn't enough, the bottleneck is usually image-heavy pages. Crop to the actual content area first, then compress. Pages with whitespace around photos still encode the whitespace, which is wasteful.

Will the recipient see anything different?

They see a PDF that opens like any other. The only visible change is at Medium and above — text becomes non-selectable. Layout, page count, page numbers, watermarks: all preserved.

What about attaching multiple files instead of merging?

It works, but mail servers count the total of all attachments against the cap. Merging means one filename to keep track of and a single click for the recipient to download.

Optimize PDFs for email — without uploading them anywhere · SnapToolz Guides

The 25 MB problem

Gmail caps attachments at 25 MB. Outlook 365 caps at 20–25 MB depending on the plan. Most corporate Exchange deployments are stricter — 10 MB is common, and the bounce-back message arrives a few minutes after you sent the email, by which point you've already moved on.

The standard fix is uploading the PDF to Drive or Dropbox and pasting a link. That works, but it leaves a copy of your document on someone else's servers, often without an expiry date, and the recipient has to be logged in to view it. For sensitive material — signed contracts, tax forms, ID scans — that's a real trade-off.

The local-first version, in three steps

1. Merge — combine the PDFs in the order you want them in.
2. Compress — bring the result under your mail server's cap.
3. Check + send — verify the size and download.

All three steps run in your browser. The result is a single PDF on your disk that you attach to the email like any other file. The recipient gets the actual document, not a link, and can open it offline.

Step 1 — Merge

Open the Merge PDFs tool, drop the files, and drag them into the order you want. Memory-safe streaming means the tool handles ten 200 MB PDFs without crashing your phone — it processes one file at a time rather than holding them all in memory at once.

Once you click Merge, the output appears as a download. If you've started the Optimize PDF for Email workflow from the Workflows page, the result is automatically handed to the next step without a manual download / re-upload — the file just carries through.

Step 2 — Compress

There are three quality presets. Low strips metadata and re-encodes images conservatively (typically 10–25% smaller, text stays crisp). Medium rasterises pages to JPEG at a balanced quality (30–55% smaller, text stays readable but is no longer selectable). High is aggressive JPEG (55–80% smaller, best for image-heavy PDFs).

For email, Medium is the sweet spot for most documents. The savings line under the download button tells you what you got — if the result is still over the cap, jump to High and try again. The original file is untouched the whole time; you can experiment as many times as you want.

Step 3 — Check and send

The download card shows the final file size next to the original — "compressed report.pdf · 8.2 MB (was 41.3 MB) · 80% smaller". If you're under 20 MB, you're safe on virtually every mail server; under 10 MB and you're safe on the strict ones too.

Attach the result to your email the normal way. The recipient sees a regular PDF, no link, no "sign in to view". That matters more than it sounds — "sign in to view" is the first thing recipients quietly delete.

When to pick a different approach

If the PDF is mostly text and is still huge after High compression, the underlying document probably has scanned page images embedded. Run OCR first to extract the text layer, then compress — the result is dramatically smaller because text encodes in kilobytes where images encode in megabytes.

If the recipient needs to fill in fields or sign, send them the un-compressed version. Compression at Medium and above rasterises form fields away.

Tools used in this guide

Run it as a workflow

Optimize PDF for email
Merge several PDFs into one, then compress to a size mail servers actually accept.

FAQ

Does compression damage the document?: Low is lossless — text remains selectable and crisp. Medium and High rasterise pages to JPEG, which makes text non-selectable but still readable. For a signed contract you want to keep editable, stick to Low.
How do I get under 5 MB?: If 'High' isn't enough, the bottleneck is usually image-heavy pages. Crop to the actual content area first, then compress. Pages with whitespace around photos still encode the whitespace, which is wasteful.
Will the recipient see anything different?: They see a PDF that opens like any other. The only visible change is at Medium and above — text becomes non-selectable. Layout, page count, page numbers, watermarks: all preserved.
What about attaching multiple files instead of merging?: It works, but mail servers count the total of all attachments against the cap. Merging means one filename to keep track of and a single click for the recipient to download.