There's two parts, the actual downtime and the SLA agreement...

At my day job, we have a calendar integration that polls Microsoft's Graph API across hundreds of Microsoft 365 tenants. We saw our first metric spike in 5xx errors at 2026/11/12 17:33 UTC. As of writing it's 2026/11/13 09:44 UTC and we are still encountering a full outage, so 16 hours and 11 minutes.

With a SLA calculator [1], assuming no other downtime this month and entering 16h11m, we get:

* Yearly SLA: 99.82%

* Monthly SLA: 97.78%

Next, what is the actual agreement? I found an SLA document list here [2].

I downloaded Service Level Agreement for Microsoft Online Services (WW) English (2026/10/01). There's a heading for Exchange Online that says:

Uptime Percentage : Service Credit

< 99.9% : 25%

< 99% : 50%

< 95% : 100%

Which seems to agree with what the original commenter said for this month.

[1] https://uptime.is/reverse

[2] https://www.microsoft.com/licensing/docs/view/Service-Level-...

We need to get beyond the arguments of 364 vs 365 and develop a new equilibrium in terms of availability that accounts for humans being equipped with these new found breaks as we spend time off of work.

https://techcrunch.com/2026/01/05/microsofts-nadella-wants-u...

The running joke in my last shop a few years ago was "Office 265"

Microsoft Outofluck