Systems and methods for assessing user activity using dynamic windowed forecasting on historical usage. The system includes a server including an electronic processor. The electronic processor is configured to receive, from a network server hosting at least one application for a plurality of users, a data stream including a plurality of historical activity indicators for the plurality of users, the plurality of historical activity indicators including a plurality of unique user identifiers and a plurality of timestamps. The electronic processor is configured to group the plurality of historical activity indicators into a plurality of historical windowed data points based on the plurality of timestamps. The electronic processor is configured to determine a forecasted quantity of users for a forecast time window based on the data points and the plurality of unique user identifiers. The electronic processor is configured to transmit the forecasted quantity of users to a user device.