What are Exchange Online's sending limits for new tenants?
Exchange Online caps how many external recipients a tenant can send to in a 24-hour sliding window. Microsoft calls it the Tenant External Recipient Rate Limit (TERRL). The standard quota is 500 × (licenses0.7) + 9500. Under changes Microsoft scheduled to begin rolling out on 14 September 2026, a tenant less than 31 days old gets 10% of that quota, a tenant 31 to 60 days old gets 25%, and trial tenants are limited to 500 external recipients a day regardless of license count. Every figure on this page is Microsoft's, quoted from the two public pages linked beside it.
What Microsoft changed
Update Aug 13, 2026: To further strengthen protection against abuse and ensure fair use of Exchange Online resources, we are updating how the Tenant External Recipient Rate Limit (TERRL) quota is calculated for certain tenants. These changes will begin rolling out starting September 14, 2026. Also, TERRL rollout has been postponed for the following environments: GCC, GCCH, DoD, and 21Vianet.
Source: Introducing Exchange Online Tenant Outbound Email Limits, Microsoft Exchange Team Blog (post updated 25 August 2026), fetched 2026-11-01.
Microsoft announced the same change to admins as Microsoft 365 message center item MC1454397. Message center needs an admin sign-in, so this page quotes Microsoft's public Exchange Team blog post, which carries the same figures.
The standard quota
Standard calculated quota for all other tenants: Daily outbound limit is based on the tenant’s email licenses (any Exchange Online or Exchange Online Protection license). More licenses increase the number of external recipients your tenant can send to per day, but at a decreasing rate per license.
500 * (Number of Non-trial Email Licenses^0.7) + 9500
Source: Introducing Exchange Online Tenant Outbound Email Limits, Microsoft Exchange Team Blog (post updated 25 August 2026), fetched 2026-11-01.
Microsoft's sample values from the same post:
| Non-trial, non-EDU email licenses | Tenant External Recipient Rate Limit |
|---|---|
| 1 | 10,000 |
| 2 | 10,312 |
| 10 | 12,006 |
| 25 | 14,259 |
| 100 | 22,059 |
| 1,000 | 72,446 |
| 10,000 | 324,979 |
| 100,000 | 1,590,639 |
Source: Introducing Exchange Online Tenant Outbound Email Limits, Microsoft Exchange Team Blog (post updated 25 August 2026), fetched 2026-11-01. We recomputed every row from the formula and each one matches when rounded to the nearest whole number.
New tenants: 10%, then 25%, then the full quota
New Tenant Quotas: For newly created tenants, the calculated TERRL quota will be temporarily reduced during the initial onboarding period:
Source: Introducing Exchange Online Tenant Outbound Email Limits, Microsoft Exchange Team Blog (post updated 25 August 2026), fetched 2026-11-01.
| Tenant age | Applied quota |
|---|---|
| Less than 31 days | 10% of standard calculated quota |
| 31-60 days | 25% of standard calculated quota |
| More than 60 days | 100% of standard calculated quota |
Source: Introducing Exchange Online Tenant Outbound Email Limits, Microsoft Exchange Team Blog (post updated 25 August 2026), fetched 2026-11-01.
Worked example, our arithmetic on Microsoft's figures: a tenant with one email license has a standard quota of 10,000. At 10% that is 1,000 external recipients in any 24 hours for its first 30 days, and at 25% it is 2,500 until day 60.
Trial tenants, and where Microsoft's pages disagree
Trial tenants: Limited to 500 total external recipients per day, regardless of license count.
Source: Introducing Exchange Online Tenant Outbound Email Limits, Microsoft Exchange Team Blog (post updated 25 August 2026), fetched 2026-11-01.
Microsoft's Exchange Online limits page, last updated 2026-10-19, still gives the older figure:
The limit for trial tenant is capped at 5,000 external recipients per day.
Source: Exchange Online limits, Microsoft Learn (last updated 2026-10-19), fetched 2026-11-01.
The two pages disagree by a factor of ten. The blog post describes the September 2026 change; the limits page has not been edited to match it. Until Microsoft reconciles them, plan for 500.
Tenants with free EDU licenses
Quota Formula for Tenants with Free EDU Licenses: For tenants that have free Education licenses (such as Microsoft 365 A1), the quota calculation will be updated to account for both purchased email licenses and free EDU licenses.
500 × (Purchased Email Licenses^0.7 + Free EDU Licenses^0.3) + 9500
Source: Introducing Exchange Online Tenant Outbound Email Limits, Microsoft Exchange Team Blog (post updated 25 August 2026), fetched 2026-11-01.
What counts and what does not
Every external recipient counts, including each member of a distribution group:
TERRL counts distribution group members individually. For example, if someone sends a message to a group in the tenant that has 1,000 external recipients, it will be counted as 1,000 external recipients.
Source: Exchange Online limits, Microsoft Learn (last updated 2026-10-19), fetched 2026-11-01.
The blog post lists messages that are not counted: Exchange Online journaling messages, automatic replies including Out of Office, delivery status notifications (NDRs, delivery receipts, read receipts), mail sent through Azure Communication Services email and Exchange Online High-volume Email, and notifications from Microsoft cloud applications such as SharePoint and Teams.
The quota is a baseline, not a guarantee:
The TERRL establishes base-line outbound sending limits for all tenants, but additional current and future restrictions can also occur due to factors like suspicious sending behavior, sending spam, fraudulent or excessively late payments, etc.
Source: Introducing Exchange Online Tenant Outbound Email Limits, Microsoft Exchange Team Blog (post updated 25 August 2026), fetched 2026-11-01.
What happens when you go over
Trial tenants: 550 5.7.232 - Your message can't be sent because your trial tenant has exceeded its daily limit for sending email to external recipients (tenant external recipient rate limit)
Non-trial tenants: 550 5.7.233 - Your message can't be sent because your tenant exceeded its daily limit for sending email to external recipients (tenant external recipient rate limit)
Source: Introducing Exchange Online Tenant Outbound Email Limits, Microsoft Exchange Team Blog (post updated 25 August 2026), fetched 2026-11-01.
Daily outbound email volume and quota are tracked using a 24-hour sliding window. If you exceed your limit, subsequent outbound messages will be blocked until your volume of external recipients from the last 24 hours drops below the limit. This could take minutes or up to 24 hours, depending on your email sending pattern. Here’s an example of how this works:
Source: Introducing Exchange Online Tenant Outbound Email Limits, Microsoft Exchange Team Blog (post updated 25 August 2026), fetched 2026-11-01.
How to see your own limit
- Read the report. In the Exchange admin center, open Reports, then Mail flow, then the Tenant Outbound External Recipients report. Microsoft's limits page says that is where an admin finds the tenant's TERRL.
- Know your tenant's creation date. The percentage depends on tenant age, so count the days since the tenant was created.
- Count external recipients, not messages. In Microsoft's example above, one message to a group with 1,000 external recipients counts as 1,000.
If you need more than the quota
Microsoft's own recommendation:
Based on service telemetry, most Exchange Online customers won’t be impacted. If your organization needs to send more email to external recipients than your limit allows, we recommend using dedicated high-volume email solution or purchasing additional Exchange Online licenses to cover your sending volumes.
Source: Introducing Exchange Online Tenant Outbound Email Limits, Microsoft Exchange Team Blog (post updated 25 August 2026), fetched 2026-11-01.
What we do not claim
These limits are Microsoft's. Humerly does not raise them, and we do not offer a way around them. If you are setting up a domain for a new tenant, our domain audit checks its SPF, DKIM and DMARC records; it has no effect on any Microsoft quota. Humerly's plans are on the pricing page.
Questions
What is the Exchange Online sending limit for a new tenant?
Microsoft's Exchange Team blog says a tenant less than 31 days old gets 10% of its standard calculated quota, a tenant 31 to 60 days old gets 25%, and a tenant more than 60 days old gets 100%. The standard quota is 500 × (number of non-trial email licenses^0.7) + 9500.
How many external recipients can a one-license tenant send to?
Microsoft's table gives 10,000 a day for one license. At the new-tenant rates that is 1,000 for the first 30 days and 2,500 until day 60, by our arithmetic on Microsoft's figures.
What is the limit for a trial tenant?
Microsoft's Exchange Team blog says trial tenants are limited to 500 total external recipients per day, regardless of license count. Microsoft's Exchange Online limits page, last updated 2026-10-19, still says 5,000.
What error do I get when I exceed the limit?
Trial tenants get 550 5.7.232 and non-trial tenants get 550 5.7.233. Messages to external recipients stay blocked until the count over the last 24 hours drops below the limit.
Does Humerly raise or get around these limits?
No. The limits are Microsoft's, and Humerly offers no way around them.
Reviewed by Venkat Nookala, last reviewed 2026-11-01.