Uptime / SLA Calculator
Convert uptime SLA percent (99.9% etc.) into allowed downtime per day/week/month/year.
SLA, uptime and allowed downtime
A Service Level Agreement defines the minimum uptime a provider commits to. Allowed downtime for a given period follows downtime = (1 − SLA) · period. Over a year (8,760 h): 99% tolerates 87.6 h (3.65 days); 99.9% (three nines) 8.76 h; 99.99% (four nines) 52.6 min; 99.999% (five nines) only 5.26 min. Each extra nine costs exponentially more — it forces redundancy, multi-AZ, multi-region and active-active topologies. Composite availability: a service depending on three components at 99.9% each has an effective SLA of roughly 99.7% (0.999³).
Applications and context
Used to compare cloud providers (AWS EC2 99.99%, S3 Standard 99.9% availability, Cloudflare and Fastly CDNs), to configure uptime monitors (Pingdom, StatusCake, UptimeRobot), to claim SLA credits when targets are missed, to design microservice architectures and to pick between regions.
FAQ
What does "three nines" mean? It's shorthand for 99.9% uptime — roughly 8.76 hours of downtime per year or 43.8 minutes per month.
Why is each extra nine so expensive? Going from 99.9% to 99.99% cuts allowed downtime by 10×, which usually requires hot standby, multi-region replication and tighter operational discipline.
Do scheduled maintenance windows count? Most providers exclude announced maintenance from the SLA — read the contract before claiming credits.
Related Tools
UV Resin Volume Calculator
Estimates UV resin volume needed to print an SLA or MSLA part.
Multiplication Table
Generate the multiplication table for any number. See the multiplication line by line up to any multiplier.
Roof Cover Area by Slope
Computes real roof cover area from projected area and slope in degrees.
Vampire The Masquerade Blood Points
Calculates the maximum blood pool in Vampire The Masquerade by generation.
Camping Water Calculator
Calculate how many liters of water to bring per person per day on a camping trip, based on activity level and climate. Plan supplies for hikes and camp.
Monthly Rainfall Index Calculator (mm)
Computes the average monthly rainfall index from total annual rainfall in millimeters and the number of rainy months.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.