1) You might be getting less visitors than you think. After 30 minutes, your visit counts as a new one. E.g. You browse on a site, walk away from the PC then come back two hours later.When you click on a new page or reload the current page, your visit counts as a new one.
2) You might be getting more visitors than you think. A proportion of visitors will block third party cookies (this is what GA uses to ‘tag’ you as a unique visitor) or disable Javascript to load on any site. These visitors will not be counted on GA.


