Systems and methods for dynamically and intelligently estimating analyte data from a continuous analyte sensor, including receiving a data stream, selecting one of a plurality of algorithms, and employing the selected algorithm to estimate analyte values. Estimation can be used to compensate for time lag, match sensor data with corresponding reference data, warn of upcoming clinical risk, replace erroneous sensor data signals, and provide more timely analyte information encourage proactive behavior and preempt clinical risk. The methods can be employed in a medical device including a continuous analyte sensor (10) that provides an output signal indicative of a concentration of an analyte, a receiver to which the signal is sent (12), and an input module (14) that receives the signal.