Some embodiments relate to a probabilistic random number generator. The probabilistic random number generator includes a memory cell comprising a magnetic tunnel junction (MTJ), and an access transistor coupled to the MTJ of the memory cell. A variable current source is coupled to the access transistor and is configured to provide a plurality of predetermined current pulse shapes, respectively, to the MTJ to generate a bit stream that includes a plurality of probabilistic random bits, respectively, from the MTJ. The predetermined current pulse shapes have different current amplitudes and/or pulse widths corresponding to different switching probabilities for the MTJ.