Uptime SLA Calculator
Calculate exact allowed downtime for any SLA percentage.
%
Allowed Downtime
99.9% uptime 0.1% downtime
Per Day
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Per Week
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Per Month
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Per Year
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To detect issues within your monthly budget, check every 4 min 23 sec or less.
SLA Comparison
| SLA | Per Month | Per Year |
|---|---|---|
| 99% | 7.31 hrs | 3.65 days |
| 99.9% | 43.8 min | 8.76 hrs |
| 99.95% | 21.9 min | 4.38 hrs |
| 99.99% | 4.38 min | 52.6 min |
| 99.999% | 26.3 sec | 5.26 min |
Common Provider SLAs
How to Use This Calculator
1
Enter your SLA
Type a percentage or pick a preset
2
See allowed downtime
Daily, weekly, monthly, yearly
3
Plan your monitoring
Use the suggested check interval
The 10x Rule
Each additional "nine" means 10x less downtime. Going from 99.9% to 99.99% cuts your allowed downtime from 8.76 hours/year to just 52 minutes/year.
Reverse Calculator
Had an incident? Switch to "Calculate SLA" mode, enter your downtime, and get your actual uptime percentage instantly.
Monitor Often Enough
If your monitoring checks every 5 minutes, you could burn 10% of your monthly budget before detecting an incident.
The Essentials
Three Nines
99.9% = 8.76 hours downtime/year
The 10x Rule
Each extra nine = 10x harder to achieve
Dependencies Multiply
Two 99.9% services = 99.8% max
Error Budget
At 99.9%, you get 43 min/month to "spend"
100% Is a Myth
Even best systems have some downtime
SLI → SLO → SLA
Measure → Target → Contract
Frequently Asked Questions
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