Guides

How to make a PDF small enough to email

Updated: 2026-10-14

You attach a PDF, press send, and the email bounces back: the file is too large. Here's why it happens, how to shrink the file in a minute, and what to do when shrinking isn't enough.

How big can an attachment be?

• Gmail: 25 MB per email. Anything bigger is turned into a Google Drive link.
• Outlook.com: 20 MB per email. Work accounts on Microsoft 365 usually allow 25 MB, but your company can set a lower limit.
• Yahoo Mail: 25 MB. iCloud Mail: 20 MB, with Mail Drop for bigger files.

Attachments are encoded for sending, which makes them about a third larger on the way. So a 20 MB PDF can already be too big for a 25 MB limit. Aim for under 15 MB to be safe, and remember that the recipient's mail server can have a lower limit than yours.

Why is my PDF so big?

Text takes almost no space: a 100-page contract made in Word is usually well under 1 MB. Large PDFs are nearly always large because of images: scanned pages, photos taken with a phone, or high-resolution pictures pasted into a document. A single page scanned in color at 600 DPI can be several megabytes.

That's good news, because images can be made much smaller without becoming hard to read.

Shrink the PDF in your browser

1. Open Compress PDF and drop your file on the page.
2. Choose a strength. Medium suits most documents. Strong gives the smallest file when it only needs to be readable on screen. Light keeps more detail for printing.
3. Click Compress and compare the size before and after. Download the new file.

Scans and photo-heavy PDFs usually shrink by 40–90%. The file is processed on your own device, which matters when the PDF is a bank statement, an ID or a contract.

Compression turns each page into an image, so the text can no longer be selected or searched. If you need searchable text afterwards, run the compressed file through OCR PDF.

When compression isn't enough

• Split it. Send the document in two or three emails. Split PDF can make one file per page range, or a file every N pages.
• Remove pages nobody needs. Blank pages, duplicate scans and long appendices add up. Delete PDF pages removes them in a few clicks.
• Use a share link. For very large files, upload them to a cloud drive you already use and send the link instead of an attachment.

Avoid huge PDFs next time

• Scan documents at 200–300 DPI. Higher settings make much bigger files that don't look any better on screen.
• Scan text-only pages in grayscale or black and white rather than color.
• When you add photos to a document, use them at the size they appear on the page rather than straight from the camera.