Compress PDF5 min read
How to Make a PDF Smaller for Email
Attachment too large? The real size limits of Gmail, Outlook and iCloud, and how to shrink a PDF in a minute without losing readable text.
By BoringWork · Updated
The short answer
Most email services stop at 20 to 25 MB per message, and many work inboxes accept only 10 MB. Compress the PDF so it fits under 10 MB: open Compress PDF, choose Balanced, and download the smaller copy. Text stays sharp; only images are resized.
How big can an email attachment be?
Each service sets its own limit, and the limit is for the whole message, not one file. Attachments are also encoded for sending, which makes them roughly a third bigger, so a 20 MB PDF can be refused by a 25 MB limit.
| Service | Attachment limit | What happens above it |
|---|---|---|
| Gmail | 25 MB | Gmail offers a Google Drive link instead |
| Outlook.com | 20 MB | Outlook offers a OneDrive link instead |
| Yahoo Mail | 25 MB | The file isn't attached |
| iCloud Mail | 20 MB | Mail Drop sends a download link instead |
A download link works, but it asks the other person to open another service, and links can expire. If you can, send the PDF itself, small enough to arrive in any inbox.
Why is my PDF so large?
Almost always because of images. A page of typed text takes a few kilobytes. A scanned page or a phone photo of a document is a picture, and pictures from modern cameras and scanners are far more detailed than a screen or a printer needs.
- Scans and photos: each page is a full image, often 300 dpi or more.
- Slides and brochures: large photos that were placed at full camera resolution.
- Merged documents: the same logo or background stored again on every page.
Shrink a PDF in your browser
- 01Open Compress PDFGo to Compress PDF and choose your file, or drop it on the page.
- 02Pick a levelBalanced suits email. Choose Smallest if it still doesn't fit, or Best quality if it will be printed.
- 03Download the smaller copyClick Compress. The result screen shows how much smaller it got, and your original file is unchanged.
The file is compressed by your own browser, so it never travels to a server. That matters for the documents people usually email: contracts, payslips, ID scans and medical letters.
Compress PDF
Make a PDF smaller for email and uploads, with a choice of quality.
Which level should I choose?
| Level | Image detail | Best for |
|---|---|---|
| Smallest | About 100 dpi | Email and reading on screen |
| Balanced | About 150 dpi | Most documents. Clear images, a much smaller file |
| Best quality | About 220 dpi | Files that will be printed |
Still too big?
- Try the Smallest level. Scans usually shrink by more than half.
- Remove pages you don't need to send with Organize PDF, then compress again.
- Split a long document into two emails: send pages 1 to 20, then the rest.
- If the PDF is mostly text and barely shrinks, it is probably already small. Check for one very large image, such as a full-page photo on the cover.
Questions
Text and drawings stay exactly the same. Photos and scanned pages are resized to a level you choose, so at Balanced they look clear on screen and in a normal print.
With BoringWork the PDF is compressed by your own browser and never uploaded, so nobody else receives a copy. With tools that upload your file, read their privacy policy first.
It is probably mostly text, which is already compact. Compression mainly shrinks photos and scans; a text-only PDF is usually small enough to email as it is.
Under 10 MB arrives almost anywhere, including work inboxes with strict limits. Under 20 MB works for Gmail, Outlook.com and iCloud.
Ready? Compress PDF, free.
Make a PDF smaller for email and uploads, with a choice of quality.