Who Presence Calculator

Who Presence Calculator is a multi-field tool that estimates current concurrent online users for a site or app. It is designed for admins, operations teams, and analysts who need a quick concurrency estimate for planning and dashboards.
Conceptually, the tool derives online presence from three inputs: total_users, an active_fraction representing the share of users that are active within a window, and session length (average_session_minutes). It scales this baseline online population by the ratio of the window length to the typical session length to estimate users online in that window.
Unique value lies in its simplicity, auditable assumptions, and fast run-time results without real-time event streams. Target users include site owners, product managers, capacity planners, and SREs who need to reason about peak loads, capacity needs, and engagement levels.
Core features include input validation, clear units, integer rounding for user counts, and an option to specify time zone for interpretation. Use cases include capacity planning during campaigns, dashboard population, and scenario analysis for performance testing. The tool outputs include current_online_users and occupancy_rate, which can be exported or logged in reports.