Availability Calculator
Availability Calculator
Calculate how much downtime should be permitted in your Service Level Agreement or Objective.
"In general, for any software service or system you can think of, 100% is not the right reliability target because no user can tell the difference between a system being 100% available and, let's say, 99.999% available." - Ben Treynor
Availability Cheat Sheet
| Availability level | Downtime per year | Downtime per quarter | Downtime per month | Downtime per week | Downtime per day | Downtime per hour |
|---|---|---|---|---|---|---|
| 90% | 36.52 days | 9.13 days | 3.04 days | 16.80 hours | 2.40 hours | 6.00 minutes |
| 95% | 18.26 days | 4.57 days | 1.52 days | 8.40 hours | 1.20 hours | 3.00 minutes |
| 99% | 3.65 days | 21.91 hours | 7.30 hours | 1.68 hours | 14.40 minutes | 36.00 seconds |
| 99.5% | 1.83 days | 10.96 hours | 3.65 hours | 50.40 minutes | 7.20 minutes | 18.00 seconds |
| 99.9% | 8.77 hours | 2.19 hours | 43.83 minutes | 10.08 minutes | 1.44 minutes | 3.60 seconds |
| 99.95% | 4.38 hours | 1.10 hours | 21.91 minutes | 5.04 minutes | 43.20 seconds | 1.80 seconds |
| 99.99% | 52.59 minutes | 13.15 minutes | 4.38 minutes | 1.01 minutes | 8.64 seconds | 0.36 seconds |
| 99.999% | 5.26 minutes | 1.31 minutes | 26.30 seconds | 6.05 seconds | 0.86 seconds | 0.04 seconds |