Planning

Uptime Calculator

Calculate SLA percentages, allowed downtime, and understand five-nines availability. Plan maintenance windows within your SLA constraints.

Availability Target

%
99%99.9%99.99%99.999%

How to Use

  1. 1Enter your target uptime percentage or select a common preset
  2. 2Use the slider for fine-grained control between 99% and 99.9999%
  3. 3View the allowed downtime for different time periods

Common SLA Tiers

UptimeYearlyMonthlyDaily
99%3d 15h 36m7h 18m14m 24s
99.9%8h 45m 36s43m 48s1m 26s
99.95%4h 22m 48s21m 54s43s
99.99%52m 34s4m 23s8.6s
99.999%5m 15s26s0.9s
99.9999%31.5s2.6s86ms

Achieving High Availability

  • Redundancy: Eliminate single points of failure with redundant components
  • Load Balancing: Distribute traffic across multiple servers
  • Auto-failover: Implement automatic failover mechanisms
  • Monitoring: Real-time monitoring with alerting systems
  • Maintenance Windows: Schedule maintenance within downtime budget

SLA vs Reality

An SLA is a contractual commitment, not a guarantee. Consider:

  • SLAs often exclude "scheduled maintenance" from downtime calculations
  • Compensation for missed SLAs is typically service credits, not refunds
  • Higher availability tiers require significantly more investment
  • Each additional "nine" is exponentially harder and more expensive to achieve