A complexity model for context-based adaptive variable length coding (CAVLC) and universal variable length coding (UVLC) in the H.264/AVC decoder is proposed. CAVLC and UVLC are used to code source data, i.e., quantized transformed coefficients (QTCs), and header data, respectively. CAVLC and UVLC are important in the baseline profile of the H.264/AVC codec since this profile targets at low complexity and low cost applications so that only CAVLC and UVLC are allowed to be the entropy coding tools. This model is verified experimentally. Possible applications of this model are also described. Since the entropy decoding complexity becomes significant in the high bit rate video due to more non-zero QTCs and motion vectors (MVs), one application scenario is to integrate this model into the H.264 encoder so that the encoder can estimate the possible decoding complexity and then select proper coding modes to generate the decoder-friendly bit streams, which are easy to decode for a particular decoding platform.