Understanding Service Availability
How we calculate. Availability % = (period − downtime) ÷ period × 100. The form uses the same arithmetic as the worked examples on this page. See our methodology and accuracy policy.
Real-world scenario: A typical Service Availability case uses period length 43200 and downtime 43.2. Enter the same figures below to reproduce the worked path.
What is Service Availability?
The core SLO numerator/denominator framing. Cross-link error budget tools when you also have an SLO target.
- Same units for period and downtime
- Define downtime (full vs partial)
- Maps to nines (99.9%, etc.)
The Formula
Worked Example
Common Use Cases
- SLO reporting: monthly availability
- Vendor reviews: measured vs promised
- Executive dashboards: reliability headline
Pro Tips
- Exclude planned maintenance only if the SLO allows
- Weight multi-region carefully
- Feed error-budget tools with the same downtime
Limitations: Service Availability results are educational DevOps/SRE/FinOps planning aids—not SLAs, billing guarantees, or operational policy. Confirm definitions with your platform and finance teams.
FAQ
Same as Professional uptime calculator?
Same family of math—this page stays in the DevOps/SRE cluster with error-budget siblings.
What if period is 0?
Availability is undefined—enter a positive period length.
Authoritative References
For SRE and FinOps definitions, consult:
- Google SRE books — SLOs, error budgets, toil
- DORA — delivery performance research
- FinOps Foundation — cloud cost practices