Knowledge of the amount of water ice on the lunar surface will play a crucial role in future lunar missions. The discovery of large quantities of water ice on the Moon will have very significant implications for human space exploration. In this letter, the methodology for quantification of water ice is developed. Quantification of water ice present in the permanently shadowed region (PSR) of Hermite-A Crater is done by comparing simulated dielectric constant values obtained using the Campbell model and laboratory-measured dielectric constant values of terrestrial analogue of lunar soil for various percentages of water ice content. From this analysis, it is observed that about 66.32% of the total PSR of Hermite-A Crater is covered with different percentages of water ice. In this letter, all the pixels of the PSR of Hermite-A Crater, with a spatial resolution of 7.4 m/pixel, have been mapped with their corresponding water ice content ranging from 0% to 9%.