⏱️ Uptime SLA Calculator
Enter an availability target — or tap a preset like 99.9% — to see the maximum downtime it allows per day, week, month, and year, so you know exactly how much outage budget each tier buys.
📉 Availability to Downtime Budget
What is an Uptime SLA Calculator?
An availability percentage sounds abstract until you translate it into real outage time. This calculator does exactly that, converting a target like 99.95% into the minutes and hours of downtime it permits over a day, week, month, and year — the figures behind every service-level agreement.
Use it to set realistic SLA targets, size your error budget, or sanity-check a vendor's promise. The results describe the downtime budget for planning — your provider may average differently and exclude maintenance, so verify against their published SLA.
❓ Frequently Asked Questions
What do the 'nines' actually allow?
Each nine roughly cuts allowable downtime by ten. 99% ('two nines') permits about 3.65 days of downtime a year; 99.9% ('three nines') about 8.76 hours; 99.99% ('four nines') about 52.6 minutes; and 99.999% ('five nines') about 5.26 minutes. This calculator works out the exact budget per day, week, month, and year for any target you enter.
How is the monthly downtime figured?
Months vary in length, so the calculator uses the average month of 30.44 days (365 divided by 12) to keep the monthly figure consistent year-round. Days use 24 hours and years use 365 days. Your provider's SLA might average differently, so always check their exact terms.
Does the SLA budget include planned maintenance?
It depends on the contract. Many providers exclude scheduled maintenance windows from their availability calculation, which effectively gives them more downtime than the headline number implies. Read the SLA's definitions of 'downtime' and 'availability' carefully — this tool shows the raw budget, not the contractual fine print.