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SLA Calculator

Calculate uptime, downtime, SLA compliance, and cost of outages. Essential tools for SRE and DevOps teams.

All calculations happen locally in your browser. No data is sent to any server.

Uptime to Allowed Downtime

Enter your target SLA percentage to see the maximum allowed downtime per period.

Quick select:
%
99.9000%Uptime
Three Nines3 nines (99.9%)Standard production / E-commerce

Maximum Allowed Downtime

8 hours, 45 minutes, 36 secondsper year
8 hours45 min36 sec
8.76 total hours525.6 total minutes

All Periods

Per day1 minute, 26 seconds
Per week10 minutes, 5 seconds
Per month43 minutes, 12 seconds
Per year8 hours, 45 minutes, 36 seconds

Quick Reference

99%3.65 days/year
99.9%8.77 hours/year
99.99%52.6 min/year
99.999%5.26 min/year

Understanding "Nines"

Each additional "nine" in uptime represents a 10x improvement in availability but typically requires significantly more investment in infrastructure and processes.

  • 2 nines: Basic business apps
  • 3 nines: Production systems
  • 4 nines: Critical systems
  • 5 nines: Mission-critical

Error Budget

Error budget is the amount of downtime you can "spend" while still meeting your SLA. It's calculated as:

Error Budget = 100% - SLA Target

For 99.9% SLA, your error budget is 0.1% (about 8.77 hours/year).