Uptime & Downtime Calculator

How to use the Uptime Calculator.

Using the calculator takes three steps:

1. Enter your uptime percentage - for example the target in your SLA, such as 99.9.
2. Choose what to display - the downtime that percentage allows, or the time the service is up.
3. Add your revenue (optional) - to see roughly how much the downtime costs per hour, day, month or year.

For example, 99.9% uptime allows about 8 hours and 45 minutes of downtime a year. Going to 99.99% cuts that to under an hour - try both and compare.

What is an optimal amount of uptime?.

The right target depends on what your users expect and what an outage costs you. 100% is not realistic; the goal is downtime small enough that it doesn't hurt the business or the people who rely on you.

Common benchmarks:

• 99.9% (“three nines”) - typical for websites, online shops and SaaS products.
• 99.99% (“four nines”) - for payment, banking and other critical services.
• 99.999% (“five nines”) - telecom-grade; about five minutes of downtime a year.

Each extra nine is much harder to reach: it needs redundancy and fast detection. External monitoring that checks every minute from several locations tells you how close you really are.