> ## Documentation Index > Fetch the complete documentation index at: https://documentation.onesignal.com/llms.txt > Use this file to discover all available pages before exploring further. # Sessions volume > Track how many sessions your app or website had each day, plus total sessions and average session duration, with the OneSignal Sessions volume chart. Use the **Sessions volume** chart to see how often people open your app or website and how long they stay. Sessions volume counts every session, so you get a complete picture of app activity. Navigate to **Analytics > Sessions & Retention** to view the chart. It appears below the [User retention](./retention-metrics) chart. ## Prerequisites * The OneSignal SDK is installed in your mobile app or website. See [Mobile SDK setup](./mobile-sdk-setup) or [Web push setup](./web-push-setup). * Your users have push subscriptions. OneSignal collects sessions from push subscriptions: app opens in your mobile app, and website visits from visitors subscribed to web push. Email and SMS subscriptions don't report sessions of their own. ## What the chart shows A session begins each time a user opens your app or website from a fully closed state, or reopens it after being in the background for at least 30 seconds. Returning within 30 seconds continues the current session instead of starting a new one. The chart shows one bar per day for the window you pick. The **Total sessions** and **Avg duration** cards summarize that window, and both update when you change the window. | Metric | Description | | - | - | | **Sessions** | The number of sessions that started on each day. Each bar is one UTC day. | | **Total sessions** | All sessions in the selected window. Hover over the card to see the exact count. | | **Avg duration** | Total time in use across all sessions in the window, divided by the number of sessions. | OneSignal began collecting session data on September 30, 2026. If your window reaches back before that date, a **Data collection starts** line marks the first day, and the cards count only sessions from that day on. ## How sessions are counted * **Every session counts.** Sessions volume counts every session, whether or not it is attributed to a message. To see which sessions are attributed to your messages, use **App Sessions** in [Conversion metrics](./conversion-metrics). * **Each session counts on the day it started.** Days are UTC calendar days. A session that starts before midnight UTC and ends after it counts on the first day. * **Durations follow the session event rules.** Very long durations and out-of-range times are adjusted the same way as on the profile. See [How OneSignal records session events](./session-events#how-onesignal-records-session-events). To see the individual sessions behind these numbers for one user, open their [session events](./session-events). ## Choose a window Use the window dropdown above the chart to pick **7 days**, **14 days**, **30 days**, **60 days**, or **90 days**. The chart opens on the longest window your plan allows, up to 30 days. Windows longer than your plan's session event retention show a lock icon. Select a locked window to see **Upgrade to measure sessions over a longer window.** and your upgrade options. OneSignal records session events for every app on every plan. Your plan sets how far back you can view them. | Plan | Session event retention | | - | - | | Free | 7 days | | Growth | 30 days | | Pro | 60 days | | Enterprise | 90 days | When you upgrade, you can view further back right away, up to your new plan's limit. ## FAQ ### How is Sessions volume different from App Sessions in Conversion metrics? Sessions volume shows how many sessions happened in your app. **App Sessions** in [Conversion metrics](./conversion-metrics) shows how those sessions relate to your messages, split into **Direct**, **Influenced**, and **Unattributed**. Use Sessions volume to see overall activity, and Conversion metrics to see which sessions are attributed to your messages. ### Why does the chart say "No sessions yet"? Your app has not reported any sessions yet. Sessions appear once the OneSignal SDK is installed and users with push subscriptions open your app or website. ### Why does the chart say "No sessions in this window"? Nobody opened your app during the selected window. Choose a longer window to look further back. ### Why can't I select a longer window? Your plan's session event retention is shorter than that window. See [Choose a window](#choose-a-window) for each plan's limit. ### Why does a session appear on a different day than on the user's profile? Sessions volume groups sessions by the UTC day they started. The session list on a user's profile shows times in your browser's timezone. A session near midnight can fall on a different day in each view. ## Related pages See every session a user or subscription had, with start time, end time, and duration. Measure whether users come back on the days after they were active. How OneSignal defines and counts a session. See which sessions and conversions are attributed to your messages. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.