Netcraft measures and makes available the response times of fifty leading hosting providers’ sites. The performance measurements are made at fifteen minute intervals from separate points around the internet, and averages are calculated over the immediately preceding 24 hour period.

From a customer’s point of view, the percentage of failed requests is more pertinent than outages on the hosting companies’ own sites, as this gives a pointer to reliability of routing, and this is why we choose to rank our table by fewest failed requests, rather than shortest periods of outage.

Fuller information on the measurement process and current measurements are available.