Uptime & SLA Calculator

Your details

Choose how you want to calculate. "SLA % to downtime" is the standard mode. "Reverse" gives the uptime % for a downtime budget. "Composite" finds the effective SLA when two services must both be available. "Business-hours" limits the window to your operational hours.
Your SLA target, e.g. 99.9 for "three nines". The calculator derives the maximum downtime allowed in each reporting period.
%
Downtime per dayThree nines (99.9%)
1m 26s

Maximum allowed downtime in a single 24-hour day (or business day)

Downtime per week10m 5s
Downtime per month43m 12s
Downtime per quarter2h 9m 36s
Downtime per year8h 45m 36s
_perDaySec86.4
_perYearSec31,536
_uptimePct99.9
99.9 %
Below 99%<99Two nines99-99.9Three nines99.9-99.99Four nines99.99-99.999Five nines99.999+

99.9% uptime allows 43m 12s of downtime per month.

  • Three nines is the most common SaaS SLA tier. Most cloud providers guarantee this level for standard service plans.
  • Over a full year this allows up to 8h 45m 36s of total downtime.

Next stepCombine uptime SLAs with error-rate and latency SLOs for a complete picture of service reliability.

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