Question

How are Alexa's traffic rankings determined?
Category: Traffic and Site Stats

Answer

Alexa's traffic rankings are based on the usage patterns of Alexa Toolbar users and data collected from other, diverse sources over a rolling 3 month period. A site's ranking is based on a combined measure of reach and pageviews. Reach is determined by the number of unique Alexa users who visit a site on a given day. Pageviews are the total number of Alexa user URL requests for a site. However, multiple requests for the same URL on the same day by the same user are counted as a single pageview. The site with the highest combination of users and pageviews is ranked #1.

Alexa's traffic rankings are for top level domains only (e.g. domain.com). We do not provide separate rankings for subpages within a domain (e.g. www.domain.com/subpage.html) or subdomains (e.g. subdomain.domain.com) unless we are able to automatically identify them as personal home pages or blogs, like those hosted on Geocities and Tripod. If a site is identified as a personal home page or blog, its traffic ranking will have an asterisk (*) next to it: Personal Page Avg. Traffic Rank: 3,456*. Personal pages are ranked on the same scale as a regular domain, so a personal page ranked 3,456* is the 3,456th most popular page among Alexa users.

About the Alexa Traffic Rankings

A listing of all sites on the Web, sorted by traffic...

Alexa computes traffic rankings by analyzing the Web usage of millions of Alexa Toolbar users and data obtained from other, diverse traffic data sources. The information is sorted, sifted, anonymized, counted, and computed, until, finally, we get the traffic rankings shown in the Alexa service. The process is relatively complex, but if you have a need to know, please read on.

What is Traffic Rank?

The traffic rank is based on three months of aggregated historical traffic data from millions of Alexa Toolbar users and data obtained from other, diverse traffic data sources, and is a combined measure of page views and users (reach). As a first step, Alexa computes the reach and number of page views for all sites on the Web on a daily basis. The main Alexa traffic rank is based on a value derived from these two quantities averaged over time (so that the rank of a site reflects both the number of users who visit that site as well as the number of pages on the site viewed by those users). The three-month change is determined by comparing the site's current rank with its rank from three months ago. For example, on July 1, the three-month change would show the difference between the rank based on traffic during the first quarter of the year and the rank based on traffic during the second quarter.