Some web hosting companies claim 100% uptime with their services. While this is technically possible given a small enough time frame, there is no way for a hosting company to be certain they will have 100% uptime for the duration of a server’s life.

The opposite of uptime is downtime. This is the amount of time a server is offline. Downtime can be attributed to server maintenance, technical failures at the datacenter of the hosting company, or to DDoS attacks on the hosting server.

Downtime is calculated by looking a the uptime claims of a web hosting company. For example, over the course of one year, a host that guarantees 99.9% up time will have 8 hours and 46 minutes of downtime. This can be calculated by taking the amount of hours in a year (8760) and multiplying it by the difference of 100% and the claimed amount of uptime (1.00 – .999 = .001).

When searching for web hosting, always be sure your potential host has an acceptable amount of uptime (99% or higher). This will not only keep you happy, but it will keep your visitors happy as well.