Free tool
SLA uptime calculator
Turn an uptime target into the downtime it actually allows. Enter your SLA to see the maximum permitted downtime per day, week, month, quarter, and year.
%
At 99.9% uptime, the maximum allowed downtime is:
Daily
1m 26s
of allowed downtime
Weekly
10m 5s
of allowed downtime
Monthly
43m 12s
of allowed downtime
Quarterly
2h 11m
of allowed downtime
Yearly
8h 45m
of allowed downtime
"Error budget" is the flip side of an SLA: 0.100% of the period can be spent on downtime before the target is missed.
FAQ
About uptime & SLAs
How is allowed downtime calculated?
Allowed downtime is the period length multiplied by (100% − uptime target). For example, 99.9% over 30 days allows 0.1% of 43,200 minutes, which is about 43 minutes.
What is an error budget?
An error budget is the amount of downtime an SLA permits before it is breached — the inverse of the uptime target. Teams "spend" it on changes, incidents, and maintenance.
What uptime target should I choose?
It depends on the service and its customers. Higher targets cost more to sustain; the right number balances customer expectations against the operational effort to meet it.
Monitor the uptime behind your SLA.
EverUptime verifies service health and turns failures into owned incidents, so you protect the target — not just measure it.
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