SLA & Uptime Calculator
Quickly translate service level agreement percentages into precise allowed downtime allowances, or calculate the exact availability score of an outage event. Runs 100% locally on your device — no data ever leaves your browser.
What do the "Nines" mean?
High availability targets are typically referred to as the number of "nines." A target availability of 99.9% (three nines) implies a maximum permitted annual outage budget of 8 hours, 45 minutes, and 57 seconds. In contrast, aiming for 99.999% (five nines) allows only 5 minutes and 15 seconds of total downtime per year, requiring complex, self-healing cloud architectures.
Standard Calculations
Uptime percentages are calculated over a specific calendar measurement window (usually monthly or annually). The basic formula is:
Use the inverse tool above to quickly analyze past outage incident impact records against your active customer SLAs.