Uptime / SLA Calculator
Convert an uptime percentage SLA into concrete allowed downtime per day, week, month, or year.
Results
What is it?
"Nines of availability" describes how much uptime a service guarantees. Three nines (99.9%) allows ~8.7 hours of downtime per year. Each additional nine reduces allowed downtime by roughly 90%, making each increment dramatically harder and more expensive to achieve.
How to use
Drag the slider to your SLA uptime percentage (or type it), then choose the time period. The calculator shows the total permitted downtime in hours, minutes, and seconds for that period.
Example scenario
Your cloud provider offers a 99.95% SLA per month. Selecting "Per Month" at 99.95% shows ~21.6 minutes of allowed downtime per month. If you experience 30 minutes of outage, the SLA is breached and you may be entitled to service credits.
Pro tip
Nines reference table (per year): 99% = 87.6 hr | 99.9% = 8.76 hr | 99.99% = 52.6 min | 99.999% = 5.26 min | 99.9999% = 31.5 sec. Note that scheduled maintenance windows are often excluded from SLA calculations — always read the fine print. Achieving five nines typically requires active-active redundancy across multiple availability zones.