Session
AnalyticsAlso: Visit · Web session · Browser session
Quick definition
A session is a single continuous visit to a website by a user. It begins when someone first arrives and ends when they leave or when the session timeout threshold is reached. Sessions are the foundational unit of web analytics, used as the denominator in conversion rates, pages per visit and engagement metrics.
Where it shows up in the data
A user is a person. A session is a visit. One user can have multiple sessions: returning to your site on Monday, again on Thursday and again on Saturday = one user, three sessions.
In Universal Analytics, a session ended after 30 minutes of inactivity. In GA4, sessions are event-based and reset at midnight. This is why session counts often differ between UA and GA4 for the same period.
Every session is attributed an origin: how the user got to your site. Source (google, facebook, email newsletter) and medium (organic, cpc, email) together describe the channel that brought the session.
GA4 introduced 'engaged sessions' as a replacement for the old session/bounce framework. An engaged session lasts more than 10 seconds, involves a conversion event or includes at least 2 page views. Engagement rate = engaged sessions / total sessions.
What it actually means
Almost every marketing metric that involves website performance is expressed as a rate per session: conversion rate (conversions / sessions), pages per session, average session duration and bounce rate. When sessions go up, the absolute counts of conversions, page views and engagements naturally go up too. This is why percentage rates matter more than absolute numbers: they show what proportion of sessions result in the outcome you care about.
Sessions are the starting point. What matters is what percentage of those sessions turn into something valuable.
How to calculate it
Conversion rate = Conversions / Sessions x 100 Revenue per session = Total revenue / Total sessions
Worked example. Month 1: 3,000 sessions, 60 conversions. Conversion rate = 2%. Month 2: 4,500 sessions, 54 conversions. Conversion rate = 1.2%. Traffic grew 50% but conversions fell 10% because the quality of sessions declined (lower intent traffic).
The Australian context
Australian website traffic shows pronounced seasonality. Many B2B websites see 30-40% lower session volume in January due to the summer shutdown period. This creates misleading month-on-month comparisons in January and February. Always compare to the same period in the prior year for Australian sites.
Where people get this wrong
Related terms
Common questions
What is the difference between sessions and users in Google Analytics?
Users are unique individuals tracked by a cookie or user ID. Sessions are individual visits. One user can generate many sessions. GA4 reports both, but for most business decisions, sessions is the more useful denominator because it measures each discrete visit that could result in a conversion.
Why does my GA4 session count differ from Universal Analytics for the same period?
GA4 and UA use different session definitions. GA4 sessions reset at midnight and are event-based. UA sessions reset after 30 minutes of inactivity and at midnight. For the same traffic, GA4 typically reports fewer sessions. This is expected and not a data error.
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New Rebellion is a marketing intelligence consultancy. We build tools, score Australian businesses on how their marketing actually performs, and publish Debrief every day. This dictionary is part of how we work in the open.
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