Uptime & SLA downtime calculator
Convert an availability target into allowed downtime, or compare observed downtime over a stated period.
Time-based arithmetic only; does not define an SLI, maintenance exclusions, user impact, service credits or contractual compliance.
Included
- Every visible input and selected unit
- Reconciled intermediate values and result breakdown
- Reproducible URL state
Not included
- Time-based arithmetic only; does not define an SLI, maintenance exclusions, user impact, service credits or contractual compliance.
What this means
Convert an availability target into allowed downtime, or compare observed downtime over a stated period.
Time-based arithmetic only; does not define an SLI, maintenance exclusions, user impact, service credits or contractual compliance.
Intermediate values are not rounded; only the localized display formats the result.
Formula & worked example
allowed downtime = period × (1 − availability target)
99.9% availability over an exact 30-day period
- Inputs
- 30 days = 2,592,000 seconds
- Calculation
- 2,592,000 × (1 − 0.999) = 2,592 seconds
The time-based downtime budget is 43 minutes 12 seconds.
How this calculation works
The calculation follows the formulas, definitions and assumptions explained on this page. The references below support the method and any stated boundaries.
Official sources
- Google SRE — Error Budget Policy — Public definitions and technical semantics used by this calculation