Uptime calculator: how much downtime does your SLA allow?
Enter an availability percentage like 99.9% to see allowed downtime per day, week, month, and year. 99% allows about 7 hours of downtime per month; 99.99% allows about 4 minutes 23 seconds.
99.9% availability allows 43 m 50 s of downtime per month.
1 m 26 s
10 m 5 s
43 m 50 s
8 h 46 m
Downtime by availability target
Average calendar month calculated at 30.44 days; year calculated at 365.25 days.
| Availability | Per day | Per week | Per month | Per year |
|---|---|---|---|---|
| 99% | 14 m 24 s | 1 h 40 m 48 s | 7 h 18 m | 3 d 15 h 40 m |
| 99.5% | 7 m 12 s | 50 m 24 s | 3 h 39 m | 1 d 19 h 50 m |
| 99.9% | 1 m 26 s | 10 m 5 s | 43 m 50 s | 8 h 46 m |
| 99.95% | 43 s | 5 m 2 s | 21 m 55 s | 4 h 23 m |
| 99.99% | 9 s | 1 m | 4 m 23 s | 52 m 36 s |
| 99.999% | 0.9 s | 6 s | 26 s | 5 m 16 s |
Measuring uptime against your SLA
1. Define "Down"
Is an endpoint down if it returns a 500 error? If latency spikes above 2 seconds? Document exact criteria in your customer service level agreement.
2. Maintenance Windows
Exclude scheduled maintenance from unplanned downtime by announcing maintenance windows in advance on your StatusEagle status page.
3. Check Interval
A 5-minute check can let a 4-minute incident slip by undetected. 60-second checks give the precision needed to defend your 99.9% uptime claims.
Frequently asked questions
Still deciding? Start monitoring free and verify your first service in ~2 minutes.
99.9% availability allows up to 43 minutes and 50 seconds of unplanned downtime per month, or roughly 8 hours and 46 minutes per calendar year.
Your first monitor takes about two minutes.
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