# - A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z

Refers to the amount of time within a specific period that a hosting provider's system is active or available for servicing site visitors. All hosts must have some downtime for routine maintenance or unexpected outages. The most reliable hosts will guarantee 99.9% uptime. Practically speaking anything less than that means a host is not competent or has insufficient reources.

What does Uptime Guarantee really mean?
99.5% uptime guarantee = 216 minutes of downtime in a month
99.8% uptime guarantee = 86.4 minutes of downtime
99.9% uptime guarantee = 43.2 minutes of downtime
99.99% uptime guarantee = 4.32 minutes of downtime
99.999% uptime guarantee = 0.432 minutes (26 seconds).

Previous Web Hosting Term: Upload
Next Web Hosting Term: URL - Uniform Resource Locator