When consumers are shopping for a website, email or specialized host, they’ll see uptime listed as a feature or perk. A lot of web hosts advertise their server availability as a way to lure in new customers. Uptimes of 95% or greater are typical for many hosts. This percentage refers to the amount of time that websites on the host’s servers are connected to the Internet, meaning that a customer’s website and other associated services — including email — are available to access.

To calculate percentages, companies compare the amount of time that their servers are accessible to the total amount of time in a specific period. Monthly measurements periods are common. Hosting customers can also use those numbers to determine the maximum amount of unavailability their website will experience during a given period. This is calculated by multiplying the number of minutes in the time period — a month in this case — by the server unavailability percentage and dividing by 100.

In the sample of 99.% time up, the equations is as follows:

43200 x .1/100 = 43.2

Thus, your website or email would not be available to edit or visit for just under 45 minutes per month, assuming that your host provides accurate percentages about how frequently their servers go down. However, your website might not go down at all.

As long as the configuration and connection work, a server should be up. All the websites and other services on that server should work if they are not experiencing specific issues. Some website owners extend the definition of server to time that their websites are unavailable specifically. While the server may be functioning correctly, a website might be down because of a script issue, maintenance or even a Denial of Service (DDOS) attack. If you’ve recently purchased a new domain or are moving between hosts, this could cause your site to be down for up to 72 hours.

The causes of website unavailability fall into several basic categories: configuration errors, hardware failure, hackers, natural disasters and maintenance. A good host monitors servers and fixes issues as soon as they arise. Hosts who keep redundant backups can also minimize downtime for your website. Many hosts offer a guarantee, often called a service level agreement, or SLA. If your website does go down more frequently or for longer than their advertised percentage, you may qualify for your money back.

Pauses in website accessibility can be minor, but they might also be serious if you sell items or serve ads on your website and require this revenue for your company. The longer your website is down, the longer you’re without this source of revenue. If it’s your only source of revenue, choosing a host that has the maximum amount of proven uptime is definitely essential!