Free tool
Uptime and SLA calculator
Enter an availability percentage to see the downtime it allows per year, month, week and day. No account needed.
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.