
New Exchange Online outbound limits for New Tenants - Limitted to 10% first month!
Microsoft's tightening the Tenant External Recipient Rate Limit (TERRL) further, starting Sept 14, 2026. This one specifically targets new tenants, trial tenants, and EDU tenants, not existing tenants.
Quick summary:
- New tenants get a ramped quota: 10% in the first 31 days, 25% for days 31–60, full quota after that
- Trial tenants drop from 5,000 to 500 external recipients/day
- EDU tenants (free A1 licenses etc.) get a separate formula that weighs purchased licenses way more heavily than free ones
Wrote up the details and some worked examples on the formula since the EDU math is a bit counterintuitive: https://lazyadmin.nl/office-365/exchange-online-tightens-outbound-limits-for-new-trial-and-edu-tenants/