Uptime SLA Calculator
Enter an SLA percentage to instantly see how much downtime is allowed per month and per year. Essential for engineering teams defining reliability targets and incident SLAs.
How this is calculated
Allowable downtime = (1 − SLA%) × minutes in period.
This calculator uses 43,800 minutes per month (365.25 ÷ 12 × 24 × 60) and
525,960 minutes per year (365.25 × 24 × 60) for accuracy across leap years.
Common SLA Reference Table
Standard industry SLA levels and their allowable downtime windows.
| SLA | Downtime / Month | Downtime / Year |
|---|---|---|
| 99% | 7h 18m | 3d 15h 39m |
| 99.5% | 3h 39m | 1d 19h 48m |
| 99.9% | 43m 48s | 8h 45m 57s |
| 99.95% | 21m 54s | 4h 22m 58s |
| 99.99% | 4m 22s | 52m 35s |
Values use 43,800 min/month and 525,960 min/year. Actual contractual values may vary by provider.
What your SLA actually means
Detection time matters
A 99.9% SLA gives you 43.8 minutes of downtime per month. If your monitoring tool takes 12 minutes to detect an outage, you've already used 27% of your SLA budget before you even know there's an incident.
Region vs. global availability
An outage affecting only one region may not breach your global SLA — but it still costs you revenue and user trust. Multi-region monitoring shows you the full picture, not just the global average.
Downtime has a cost
Every minute of downtime is revenue at risk. For a SaaS business doing $100K/month, 43.8 minutes of downtime per month at 99.9% costs roughly $3,000 in potential lost revenue at that rate.
Know the moment your SLA is at risk.
MonitorGiant monitors your sites, APIs, and services around the clock — alerting you the moment something breaks, so you can act before your SLA window closes.
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