Using forensic probabilistic tools to identify a DNA sample’s number of contributors (NOC) is crucial to an accurate computation of the weight of evidence for a person of interest. Traditionally, calculating the NOC for a forensic short tandem repeat (STR) DNA profile involves evaluating peaks per locus and dividing by two, ratios of alleles, allelic balance at a locus, and review to ensure all loci fit the estimated NOC; however, this method provides only an estimate about the minimum NOC that could explain the mixture rather than the probability of a certain NOC; and there can be variation between analysts, which introduces subjectivity when using this method to determine NOC. The Rutgers research developed and validated a probabilistic system called “NOCIt,” which determines a probability distribution on the NOC given an STR electropherogram. NOCIt incorporates models of peak height, forward and reverse stutter, and noise and allelic drop-out, in addition to accounting for the number of alleles, so it is considered a fully continuous system. NOCIt trial licenses and all mixture data are available free to the forensic community for implementation and validation purposes.