Uptime and SLA calculator
Enter an availability percentage to see the downtime it allows per year, month, week and day.
The percentage in your SLA or target.
Per year
8 h 45 min
Per month
43 min 50 s
Per week
10 min 5 s
Per day
1 min 26 s
Common availability levels
| Availability | Per year | Per month | Per week | Per day |
|---|---|---|---|---|
| 99% | 3 d 15 h | 7 h 18 min | 1 h 40 min | 14 min 24 s |
| 99.5% | 1 d 19 h | 3 h 39 min | 50 min 24 s | 7 min 12 s |
| 99.9% | 8 h 45 min | 43 min 50 s | 10 min 5 s | 1 min 26 s |
| 99.95% | 4 h 22 min | 21 min 55 s | 5 min 2 s | 43.2 s |
| 99.99% | 52 min 36 s | 4 min 23 s | 1 min | 8.6 s |
| 99.999% | 5 min 16 s | 26.3 s | 6 s | 0.9 s |
How to read it
A year counts 365.25 days and a month is a twelfth of it. Each extra nine costs far more to reach than the last: compare what the outage really costs you with what the higher level takes, and check how your provider measures it.
Questions
- How much downtime does 99.9% allow?
- About 8 h 45 min per year, or 43 min 50 s per month.
- How much downtime does 99.99% allow?
- About 52 min 36 s per year, or 4 min 23 s per month.
- Does planned maintenance count?
- It depends on your SLA: many exclude announced maintenance windows from the calculation. Read how yours defines availability and how it is measured.
- How does an SLA relate to the RTO?
- The recovery time objective must fit within what the SLA allows: a 4-hour RTO cannot support an SLA allowing 43 minutes a month, unless failures are very rare and the terms allow for it.