Uptime Calculator
What does your SLA uptime percentage actually mean in real downtime?
SLA Reference Table
| SLA Level | Monthly Downtime | Yearly Downtime |
|---|---|---|
| 99% | 7h 18m | 3d 15h |
| 99.5% | 3h 39m | 1d 19h |
| 99.9% (Three Nines) | 43.8 minutes | 8h 46m |
| 99.95% | 21.9 minutes | 4h 23m |
| 99.99% (Four Nines) | 4.4 minutes | 52.6 minutes |
| 99.999% (Five Nines) | 26.3 seconds | 5.3 minutes |
Understanding Uptime SLA Percentages
Service Level Agreements (SLAs) define the expected uptime for cloud services, typically expressed as a percentage. While the difference between 99.9% and 99.99% might seem small, it represents a 10x difference in allowed downtime — from 8.7 hours per year to just 52 minutes.
What Does 99.9% Uptime Mean?
A 99.9% uptime SLA (commonly called "three nines") allows for approximately 8 hours and 45 minutes of downtime per year, or about 43 minutes per month. This is the most common SLA tier for production cloud services like AWS, Google Cloud, and Azure.
What Does 99.99% Uptime Mean?
A 99.99% uptime SLA ("four nines") allows only 52 minutes of downtime per year. This premium tier is typically offered for critical infrastructure services and often comes with financial credits if the provider fails to meet it.
Why Monitoring Matters More Than SLAs
SLAs are promises, not guarantees. Even services with 99.99% SLAs experience outages that exceed their targets. The real question isn't whether your dependencies will go down — it's how quickly you'll know about it. Statusfield monitors your third-party services continuously so you can respond to outages before your customers notice.