How to compress a PDF so it fits in an email
Attachment limits are smaller than most people expect, and they apply to the encoded message rather than the raw file. Here is what each provider actually allows, and how to get a PDF under the line without paying for anything.
Drag and drop here, or choose from your device.
Up to 50 MB per file. Files are processed in your browser.
Full options and FAQs on the Compress PDF page.
The attachment limits you are actually hitting
- Gmail: 25 MB per message, but attachments are base64-encoded, so a file above roughly 18 MB can still fail. Above the limit Gmail swaps in a Drive link instead of attaching.
- Outlook.com: 20 MB per message. Microsoft 365 accounts default to 25 MB, and an administrator can lower this.
- Many corporate mail servers cap inbound mail at 10 MB, which is why a message can leave your outbox and bounce later.
- Practical target: get under 10 MB and your PDF will pass almost everywhere.
Why the file is big in the first place
A text-only PDF exported from a word processor is usually well under 1 MB. Files that balloon to 20 MB or more are nearly always image-heavy: a scanned contract, a photographed document, a slide deck full of screenshots, or a design export at print resolution.
That matters because it tells you what to do. Compressing images inside the file is what recovers space; there is very little to squeeze out of plain text.
Compress, or split?
If your PDF is one long scanned document and the recipient only needs part of it, splitting is better than compressing — you keep full quality and send a fraction of the pages. Compress when the whole document must arrive intact.
Step by step
- 1Add your PDF to the compressor below.
- 2Start with the medium level — it usually gets a scan down by 60-80% while staying easy to read.
- 3Check the reported new size. Aim for under 10 MB.
- 4If it is still too large, try the strongest level, or split the document and send it in two messages.
- 5Open the result before sending and confirm small print is still legible.
Frequently asked questions
- Will compressing make the text unreadable?
- At the lighter levels, no — body text stays sharp. The strongest level noticeably softens fine print, so check the result before sending anything with signatures, stamps or small footnotes.
- Can I compress a PDF on my phone?
- Yes. The tool runs in the mobile browser, so you can shrink a scan on Android or iPhone without installing an app. Very large files take longer on phones because compression uses the device's own processor.
- Is my document uploaded anywhere?
- No. The compression runs in your browser with JavaScript. The file is never sent to a server, which is why it also works with the network disconnected once the page has loaded.