Everything You Need to Know About 99.9% Uptime

Jan 20, 2023


Have you ever heard the term “99.9% uptime” and wondered what it meant? If you’re a business owner understanding the concept of 99.9% uptime is important. This number isn’t just a random figure that companies throw around when marketing their products and services; rather, it has real implications for how often your website will be available and running smoothly. Let’s take a look at what 99.9% uptime means and how it affects your website.

What is Uptime?

Uptime simply refers to the amount of time that your website is available for visitors to access without any issues or disruptions in service. A website with 100% uptime would always be running without any sort of downtime or outages, while websites with lower levels of uptime can experience occasional outages due to server maintenance or other technical issues. As such, having an understanding of what levels of uptime are acceptable is important when choosing a hosting provider for your website.

Calculating Uptime

The percentage of uptime is calculated by taking total seconds in a month divided by total seconds available in a month (30 days x 24 hours x 60 minutes x 60 seconds). In order to calculate the actual amount of downtime that can occur during this period, one must subtract the percentage from 100%.


Let’s say you monitored a website during 30 days  (which translates to 2592000 seconds), and in that time frame the website went down for 60 minutes (60 x 60 = 3600 seconds). To define the uptime and downtime percentages, the following calculation is performed:

Total time your website was down: 3600 seconds
Total time your website was monitored: 2592000 seconds
Downtime percentage = 3600 seconds / 2592000 seconds = 0.00139 (percentage 0.00139×100) = 0.14%
Uptime percentage = 100% – 0.14% = 99.86%

How Does Uptime Affect Your Website?

Having an understanding of 99.9% uptime (also called the three 9’s) is important because it impacts how reliable and available your website will be for visitors who are trying to access it online. The higher the level of uptime that your hosting provider offers, the fewer times that visitors will encounter errors or disruptions when trying to view your site—which translates into better customer satisfaction rates and more successful visits! Additionally, having higher levels of uptime also helps ensure that any e-commerce transactions on your site are secure and uninterrupted so customers feel safe making purchases on your site as well as returning again in the future!


In conclusion, understanding what 99.9% uptime means is essential for businesses owners who want their websites to run optimally without experiencing frequent outages or disruptions in service due to low levels of uptime. A 100% uptime guarantee is impossible as maintenance will still be needed on servers so its important to know how the uptime guarantee of your hosting provider actually is calculated, ask them about this.

Curious about how 040Hosting is calculating its uptime ? Our monitoring systems will monitor the servers 24×7 and based on this our uptime is show on this page. An important note here is that the uptime shown here is real uptime, so also maintenance time is calculated within the 100% ; so if maintenance did take 1 hour in a month to complete the uptime would be 99.86%. Want to know more contact our technical team here.


Questions? We can help.