Enter an uptime target to see how much downtime your SLA actually allows per day, month, and year.
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A 99.9% ('three nines') SLA allows about 43.8 minutes of downtime per month, or roughly 8.77 hours per year. Each extra nine cuts that by about 10×.
Allowed downtime = (1 − uptime%/100) × the time period. The calculator applies this to a day, a 30-day month, and a 365-day year.