A quantitative approach is presented here that studies the H trapped by the precipitates of microalloying elements (Nb, Ti, and V) in low C ferritic steels. Three model steels, each with one of the three microalloying elements, were prepared in the laboratory and subjected to aging treatment after solutionizing to achieve precipitates in ferrite. The precipitation reactions in the alloys were simulated using the TC-PRISMA module in Thermo-Calc software (databases: TCFE11 and MOBFE6) and subsequently validated using a small-angle neutron scattering (SANS) study. The H trapping abilities in the aged alloys were estimated after saturation H charging using electrochemical means and correlated with the volume fraction, number density, size, and interface character of the precipitates (all estimated using SANS). The relative H trapping ability of the precipitates was estimated as TiC > NbC > VC. The optimum aging conditions to achieve the best H trapping abilities were identified. Moreover, the maximum number of H atoms that can be trapped at the precipitate-ferrite interfaces were estimated based on the geometric considerations using SANS-estimated precipitate quantifications for each alloy. Subsequently, it was argued that the total quantity of trapped H by these precipitates can be explained if H remains trapped within the precipitate bodies in addition to those trapped at interfaces.