Email Attachment Size Limits You Need to Know
Every email provider has a maximum file size for attachments. If your PDF exceeds the limit, the email will bounce or refuse to send. Here are the most common limits:
- •Gmail: 25MB per email (total for all attachments combined)
- •Outlook / Hotmail: 20MB per email
- •Yahoo Mail: 25MB per email
- •Apple iCloud Mail: 20MB per email
- •Corporate email servers: Often 10MB or even 5MB, depending on company policy
If your recipient uses a corporate email system, aim for files under 10MB to be safe. You can also try compressing your PDF for email before splitting.
How to Split a PDF for Email (Step by Step)
Upload your oversized PDF
Go to OmnisPDF's Split PDF tool and upload your file. You'll see the total page count and can preview each page. Free users can upload files up to 25MB; Pro users up to 200MB.
Divide it into email-friendly parts
Split the PDF into page ranges that keep each part under the email size limit. For example, split a 60-page, 40MB PDF into three 20-page sections. Each section should be roughly 13MB — well under Gmail's 25MB limit.
Download and send each part separately
Download each split file. Attach Part 1 to your first email, Part 2 to a second email, and so on. Name the subject lines clearly: "Document - Part 1 of 3", "Document - Part 2 of 3", etc.
Should You Compress or Split? (Or Both)
Before splitting your PDF, try compressing it first. Compression can reduce file sizes by 50-80%, which might bring your PDF under the email limit without splitting at all.
Try compressing first
Use Compress PDF to reduce the file size. If your 30MB PDF compresses to 18MB, you can email it through Gmail without splitting. For even more targeted compression, try Compress to 5MB or Compress to 2MB.
Split if compression isn't enough
If your compressed PDF is still too large — for example, a 100-page document with high-resolution scans — splitting is the way to go. Split the document into logical sections (chapters, sections, or equal page counts).
Compress then split for best results
For the smallest possible files, compress first, then split. This gives you the fewest number of email parts while keeping each one well under the size limit.
How the Recipient Can Recombine the Parts
After you send split PDFs, the recipient will need to merge them back into one document. Include a note in your email with these instructions:
- ✓ Download all parts from each email to the same folder.
- ✓ Go to OmnisPDF Merge PDF and upload all the parts.
- ✓ Arrange them in order (Part 1 first, Part 2 second, etc.).
- ✓ Click Merge and download the complete document.
The whole process takes less than a minute, and the merged PDF will be identical to your original.
Pro Tips for Emailing Large PDFs
- ✓ Flatten before splitting. If your PDF has form fields or annotations, use Flatten PDF first to reduce embedded data.
- ✓ Convert images to JPG. If you only need to share visual pages (not editable text), convert pages to JPG images — they are often much smaller than PDF pages.
- ✓ Use clear file names. Name your files "Report_Part1of3.pdf", "Report_Part2of3.pdf", etc. so the recipient knows the order.
- ✓ Extract only what's needed. If the recipient only needs certain pages, extract those pages instead of sending the full document.
- ✓ Test with yourself first. Send the split files to your own email to make sure everything looks right before sending to the recipient.