// how much downtime is

99.9% uptime = 8.8 h down per year.

That's 3.0 nines. Allowed downtime at 99.9% availability:

per year8.8 h
per month43.8 min
per week10.1 min
per day1.4 min

The neighborhood

what one more nine buys you
90%36.5 days/yr
99%3.7 days/yr
99.5%43.8 h/yr
99.9% ← you are here8.8 h/yr
99.95%4.4 h/yr
99.99%52.6 min/yr
99.995%26.3 min/yr
99.999%5.3 min/yr

Azure services live at specific rungs of this ladder — see the SLA dataset, or compute the composite for your whole environment from one Resource Graph query.

ⓘ Designed availability, not a guarantee.