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-...

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sugarkjube a day ago | parent [-]

> Uptime Percentage : Service Credit > < 99.9% : 25% > < 99% : 50% > < 95% : 100%

These targets feel very very low nowadays.

99% uptime for email means 3.5 days/ year no email.

(although 99.9 = about 8 hours/year would seem bearable - but maybe not for a company like microsoft)

	▲	moebrowne a day ago \| parent [-]
		> 99% uptime for email means 3.5 days/ year no email Depends on how it appears, if it was one or several large chunks that is much more disruptive than minutes per day. 3.5 days/year is equivalent to less than 15 minutes/day. It sucks no matter how you slice it, but the severity/impact depends on more than the aggregate downtime.