Uptime and downtime with 99 % SLA

2025-11-27:

It's always DNS. I built uptime mongers to monitor the DNS security issues that standard services ignore: parent zone delegation changes, stale DNSSEC signatures, expired RRSIGs. Get alerted when nameservers change at your registrar without your permission.

SLA & Uptime Calculator

How much downtime corresponds to your SLA?

%

(enter SLA level and hit the <enter> key)

SLA level of 99 % uptime/availability results in the following periods of allowed downtime/unavailability:

Daily
14m 24s
Weekly
1h 40m 48s
Monthly
7h 18m 17s
Quarterly
21h 54m 52s
Yearly
3d 15h 39m 30s

Direct link to the page with these results: uptime.is/99 uptime.is/two-nines

The SLA calculations assume a requirement of continuous uptime (i.e. 24/7 all year long) with additional approximations as described in the source. uptime.is was originally implemented in newLISP, which had powered uptime and downtime calculations for more than a decade.

For convenience, there are special CEO and SEO friendly links for N nines:

three nines, four nines, five nines, six nines etc.