What an uptime SLA is really worth — downtime hours and revenue lost.
“Three nines” sounds abstract until you convert it to hours of outage and dollars lost. This tool does exactly that, and shows what buying the next nine saves. Model the redundancy spend on the container hosting calculator.
Free downtime cost calculator — an uptime SLA and your revenue to the hours of outage per year and the money each nine actually saves.
99% uptime allows 3.65 days of downtime a year; 99.9% allows 8.8 hours; 99.99% allows 52.6 minutes; 99.999% (five nines) allows just 5.3 minutes. Each additional nine cuts allowed outage roughly tenfold — and usually multiplies the engineering cost to achieve it.
Only if the revenue or reputation saved exceeds the cost of the redundancy needed to hit it. This calculator shows the annual money at stake per nine so you can compare it against multi-region failover, hot standbys and on-call cost. For many internal tools 99.9% is plenty; for checkout flows every minute counts.