Various embodiments relate to a multi-standard Viterbi decoder. Based on programmable values for constraint length, generator polynomials, and code rate, the multi-standard Viterbi decoder may adhere to a specific convolutional code standard. At a given time, the multi-standard Viterbi decoder may receive a variety of convolutional codes through a channel and may process them using various forms of the trace back method. Various embodiments include a branch metric unit and path metric unit that include a variety of sub-units that may or may not be active based on the value of the programmable value. Various embodiments also enable the multi-standard Viterbi decoder to handle different forms of convolutional codes, such as tail-biting codes. In some embodiments, the multi-standard Viterbi decoder may also process at least two convolutional codes concurrently.