How to Bypass Outlook's Attachment Size Limit

Microsoft Outlook is a staple of business communication — used by millions of professionals, enterprises, and organizations worldwide. But it comes with a frustrating restriction: Outlook limits email attachments to just 20MB (or 25MB for Microsoft 365 web). If you've ever tried to email a presentation, design file, or project archive, chances are you've hit this wall.

When a file exceeds the limit, Outlook either blocks the attachment entirely or forces you to upload it to OneDrive and share a link instead. For many users — especially those in corporate environments — this workaround creates more problems than it solves.

Why Outlook limits attachment size

Outlook enforces a 20–25MB attachment cap to manage server load and ensure email delivery reliability across Exchange servers. The exact limit depends on your setup:

  • Outlook desktop (Exchange): 20MB default (IT admins can adjust this)
  • Outlook.com / Microsoft 365 web: 20MB per file
  • Outlook mobile: 25MB in most configurations

When your file exceeds the threshold, Outlook prompts you to upload it to OneDrive and insert a sharing link. While this works in theory, it often causes issues:

  • Recipients outside your organization may not have OneDrive access
  • Company firewalls and security policies may block external cloud links
  • Shared links can expire, break, or require extra authentication
  • IT departments may restrict OneDrive sharing with external contacts
  • Recipients simply prefer real attachments they can download directly

How to send large files on Outlook without OneDrive

SendSplit provides a straightforward solution. Instead of relying on cloud links, SendSplit lets you send files up to 200MB as real email attachments — fully compatible with Outlook, Gmail, and all major email providers.

Using SendSplit is simple:

  1. Upload your file (up to 200MB)
  2. Choose a package split size (10MB, 20MB, or 25MB) — select 20MB or smaller for Outlook compatibility
  3. Enter the recipient's email address
  4. Click send

SendSplit automatically compresses and splits your file into smaller parts, then delivers each part as a real email attachment. Your recipient downloads the attachments from their Outlook inbox and extracts them to restore the original file — no cloud links, no OneDrive, no special software.

Best split size for Outlook

When sending to Outlook users, choosing the right split size matters:

  • 10MB — Safest option. Works with all Outlook configurations, including older Exchange servers with strict limits
  • 20MB — Recommended for most Outlook setups. Stays within the standard desktop limit
  • 25MB — Best for Outlook.com and Microsoft 365 web users, but may be blocked by some corporate Exchange servers

If you're unsure about the recipient's configuration, 10MB or 20MB is the safest choice.

Secure and enterprise-friendly

Unlike OneDrive sharing links that can be intercepted or misconfigured, SendSplit offers optional password protection for your attachments. This makes it ideal for:

  • Sending confidential contracts and legal documents
  • Sharing financial reports with external auditors
  • Delivering sensitive project files to clients
  • Transferring files between organizations with different IT policies

Your files are processed temporarily and automatically deleted after delivery. SendSplit never stores your data permanently, ensuring complete privacy.

Who benefits from this?

  • Business professionals sending reports, proposals, and presentations via Outlook
  • Accountants and legal teams sharing large financial or legal documents
  • IT administrators looking for a simple way to help users bypass Exchange limits
  • Freelancers and consultants delivering project files to corporate clients
  • Anyone frustrated with Outlook's attachment size restrictions

Stop wrestling with Outlook's attachment limits. Try SendSplit and send files up to 200MB as real email attachments — quickly, securely, and without OneDrive.