Uptime Calculator
Calculate system uptime and downtime periods based on availability percentage
Calculate Uptime and Downtime
System availability as a percentage (e.g., 99.9%)
Choose whether to display uptime or downtime periods
SLA Level
3 Nines
Standard
Downtime Percentage
0.100%
Downtime Periods
Daily
Weekly
Monthly
Yearly
Calculation: Downtime = (100% - Uptime%) × Time Period
Uptime fraction: 0.999000 (99.9%)
Downtime fraction: 0.001000 (0.100%)
Availability Analysis
Example Calculation
99.9% Uptime Weekly Example
Uptime: 99.9% = 0.999 fraction
Total weekly seconds: 7 × 24 × 60 × 60 = 604,800 seconds
Uptime seconds: 0.999 × 604,800 = 604,195.2 seconds
Downtime fraction: 1 - 0.999 = 0.001
Calculation Result
Downtime = 0.001 × 604,800 = 604.8 seconds
Downtime = 10 minutes and 4.8 seconds per week
This means 99.9% uptime allows ~10 minutes of downtime per week
Common SLA Levels
Time Period Reference
SLA Tips
Higher uptime requires better infrastructure and monitoring
5 nines (99.999%) is considered enterprise-grade availability
Plan maintenance windows within acceptable downtime
Monitor systems continuously to detect issues early
Consider redundancy and failover systems for critical services
Understanding Uptime and SLA
What is Uptime?
Uptime is a measurement of system availability and reliability. It represents the percentage of time a system, service, or device is operational and available to users. Uptime is typically expressed as a percentage (e.g., 99.9%) or as "nines" (e.g., "three nines").
Why Uptime Matters
- •Business continuity and revenue protection
- •User experience and customer satisfaction
- •Service Level Agreement (SLA) compliance
- •Brand reputation and trust
Uptime Calculation Formulas
Downtime % = 100% - Uptime %
Downtime = (1 - Uptime fraction) × Time period
Uptime = Uptime fraction × Time period
The "Nines" System
2 Nines (99%): Basic availability
3 Nines (99.9%): Standard for most services
4 Nines (99.99%): High availability
5 Nines (99.999%): Mission critical
6+ Nines: Extremely rare, very expensive
Calculating Different Time Periods
Example: 99.9% Weekly Uptime Calculation
Step-by-step calculation:
- 1. Calculate total seconds in a week:
- 7 days × 24 hours × 60 minutes × 60 seconds = 604,800 seconds
- 2. Convert uptime to fraction: 99.9% ÷ 100 = 0.999
- 3. Calculate uptime: 0.999 × 604,800 = 604,195.2 seconds
- 4. Calculate downtime: 604,800 - 604,195.2 = 604.8 seconds
- 5. Convert to minutes: 604.8 ÷ 60 = 10.08 minutes
Real-world impact:
Daily: ~1.4 minutes downtime
Weekly: ~10.1 minutes downtime
Monthly: ~43.2 minutes downtime
Yearly: ~8.76 hours downtime