Microsoft 365 Quarterly Uptime Number Sinks to New Low

Posted on by Tony Redmond

Microsoft 365 Uptime Suffers Major Blip in First Quarter of Calendar Year 2026

Microsoft’s service health and continuity page publishes details of Microsoft 365 Service Level Availability on a quarterly basis. The figures are worldwide for all commercial regions and reflects the combined uptime performance across all workloads. Microsoft doesn’t report details of uptime performance for individual regions. In effect, the figure is a metric for reporting and transparency purposes at a very high level instead of detailed information about a single tenant or even tenants in a single country.

Lowest Uptime Number Ever

The 99.526% figure published for Microsoft 365 uptime in the first quarter of the 2026 calendar year came as a real surprise because it was such a big drop over the performance delivered in the previous quarters (Figure 1).

Microsoft 365 uptime performance against SLA since Q1 CY2024.
Figure 1: Microsoft 365 uptime performance against SLA since Q1 CY2024

Delivering 99.526% uptime means that service interruptions clocked up approximately 614 minutes (just over ten hours) in the quarter. Not only was the figure well below the norm (performance in Q4 CY2025 was 99.954%), but it also marked the lowest figure for uptime performance since the Office 365 for IT Pros team began to track the data in 2013 (Table 1).

Q1 2013Q2 2013Q3 2013Q4 2013Q1 2014Q2 2014Q3 2014Q4 2014
99.94%99.97%99.96%99.98%99.99%99.95%99.98%99.99%
Q1 2015Q2 2015Q3 2015Q4 2015Q1 2016Q2 2016Q3 2016Q4 2016
99.99%99.95%99.98%99.98%99.98%99.98%99.99%99.99%
Q1 2017Q2 2017Q3 2017Q4 2017Q1 2018Q2 2018Q3 2018Q4 2018
99.99%99.97%99.985%99.988%99.993%99.98%99.97%99.98%
Q1 2019Q2 2019Q3 2019Q4 2019Q1 2020Q2 2020Q3 2020Q4 2020
99.97%99.97%99.98%99.98%99.98%99.99%99.97%99.97%
Q1 2021Q2 2021Q3 2021Q4 2021Q1 2022Q2 2022Q3 2022Q4 2022
99.97%99.98%99.985%99.976%99.98%99.98%99.99%99.99%
Q1 2023Q2 2023Q3 2023Q4 2023Q1 2024Q2 2024Q3 2024Q4 2024
99.98%99.99%99.99%99.996%99.97%99.99%99.977%99.927%
Q1 2025Q2 2025Q3 2025Q4 2025Q1 2026   
99.988%99.995%99.991%99.954%99.526%   
Table 1: Microsoft 365 uptime performance since 2013 (from Office 365 for IT Pros)

Microsoft’s published data for Microsoft 365 uptime only goes back to 2022, but we’ve noted the quarterly performance ever since Microsoft introduced its financially-backed guarantee for the Office 365 service (as it was at the time).

Impact on Uptime Doesn’t Mean Any Service Credits

A large drop in uptime performance in Q1 might seem staggering, but it is only an indicator that one or more largescale incidents occurred, perhaps in several regions. Certainly, the impact of the incidents was sufficient to materially affect the global uptime metric. It also doesn’t mean that Microsoft is on the hook to pay out service credits to its customers under the service level agreement for online services. When reading Microsoft documentation about availability, you might find this page to be a useful guide to how Microsoft thinks about Service Level Agreements.

Although Microsoft’s commitment is to deliver 99.9% uptime for its online services, the measurement on a per-service, per-month basis. Indeed, Calling Plans, Teams Phone, and Audio Conferencing go even higher with a 99.999% uptime, up from the 99.99% target set in 2021.

Customers can only claim service credits if a specific service like Exchange Online or SharePoint Online falls below the 99.9% threshold with the uptime percentage calculated as:

Delivering 99.526% uptime means that service interruptions clocked up approximately 614 minutes (just over ten hours) in the quarter. Not only was the figure well below the norm (performance in Q4 CY2025 was 99.954%), but it also marked the lowest figure for uptime performance since the Office 365 for IT Pros team began to track the data in 2013 (Table 1).

Q1 2013Q2 2013Q3 2013Q4 2013Q1 2014Q2 2014Q3 2014Q4 2014
99.94%99.97%99.96%99.98%99.99%99.95%99.98%99.99%
Q1 2015Q2 2015Q3 2015Q4 2015Q1 2016Q2 2016Q3 2016Q4 2016
99.99%99.95%99.98%99.98%99.98%99.98%99.99%99.99%
Q1 2017Q2 2017Q3 2017Q4 2017Q1 2018Q2 2018Q3 2018Q4 2018
99.99%99.97%99.985%99.988%99.993%99.98%99.97%99.98%
Q1 2019Q2 2019Q3 2019Q4 2019Q1 2020Q2 2020Q3 2020Q4 2020
99.97%99.97%99.98%99.98%99.98%99.99%99.97%99.97%
Q1 2021Q2 2021Q3 2021Q4 2021Q1 2022Q2 2022Q3 2022Q4 2022
99.97%99.98%99.985%99.976%99.98%99.98%99.99%99.99%
Q1 2023Q2 2023Q3 2023Q4 2023Q1 2024Q2 2024Q3 2024Q4 2024
99.98%99.99%99.99%99.996%99.97%99.99%99.977%99.927%
Q1 2025Q2 2025Q3 2025Q4 2025Q1 2026   
99.988%99.995%99.991%99.954%99.526%   

Table 1: Microsoft 365 SLA performance since 2013 (from Office 365 for IT Pros)

Microsoft’s online data only goes back to 2022, but we’ve noted the quarterly performance ever since Microsoft introduced its financially-backed guarantee for the Office 365 service (as it was at the time).

Impact on Uptime Doesn’t Mean Any Service Credits

A large drop in uptime performance in Q1 might seem staggering, but it is only an indicator that one or more largescale incidents occurred, perhaps in several regions. Certainly, the impact of the incidents was sufficient to materially affect the global uptime metric. It also doesn’t mean that Microsoft is on the hook to pay out service credits to its customers under the service level agreement for online services. When reading Microsoft documentation about availability, you might find this page to be a useful guide to how Microsoft thinks about Service Level Agreements.

Although Microsoft’s commitment is to deliver 99.9% uptime for its online services, the measurement on a per-service, per-month basis. Indeed, Calling Plans, Teams Phone, and Audio Conferencing go even higher with a 99.999% uptime, up from the 99.99% target set in 2021.

Customers can only claim service credits if a specific service like Exchange Online or SharePoint Online falls below the 99.9% threshold with the uptime percentage calculated as:

Microsoft 365 uptime formula for a service.

Claims cannot be made based on quarterly performance nor across multiple workloads. Given the work involved to gather evidence and logs, many tenants don’t bother pursuing claims, and to be fair to Microsoft, the uptime performance for online services is usually very good.

Spread of Microsoft 365 and Large Number of Users Makes Uptime Hard to Imagine

According to Microsoft’s FY26 Q2 results, Microsoft 365 now “exceeds 450 million paid seats” Taking the uptime calculation for a service, each user had 129,600 minutes to access online services in Q1 CY26. Microsoft 365 as a whole has 58.32 trillion user minutes. Losing 0.00474% of those minutes means that Microsoft 365 tenants as a whole lost approximately 276 billion user minutes in the quarter (by comparison, the figure for Q4 CY25 is approximately 27 million).

Microsoft 365 service interruptions happen all the time. The question is whether an outage affects your tenant. Given the distributed nature of the Microsoft 365 datacenter network, high availability features incorporated into workloads (like Exchange Database Availability Groups), and the distribution of tenants and workloads across the network, a single outage seldom affects more than one region. The blip in uptime availability in Q1 CY26 is a blip, but no more than that. At least, that’s what the historic uptime data tells us. Time will tell.

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