99.5% uptime: how much downtime?
An uptime of 99.5% (two and a half nines) allows 3h 39m of downtime a month and 1d 19h 48m a year.
| Period | Allowed downtime |
|---|---|
| Per day | 7m 12s |
| Per week | 50m 24s |
| Per month | 3h 39m |
| Per quarter | 10h 57m |
| Per year | 1d 19h 48m |
What 99.5% means in practice
Allows a bit over three and a half hours a month. It is what a single server with manual recovery can usually deliver, and it is a common floor for small business sites.
A year is counted as 365 days and a month as a twelfth of that. Need another percentage, or the uptime from minutes of downtime? Use the uptime calculator.