Measuring cell growth on adhesive substrates is critical for understanding cell biophysical properties and drug response. Traditional optical techniques have low sensitivity and vary in reliability depending on cell type, while microfluidic technologies rely on cell suspension. In this study, a new platform has been developed that is able to measure the weight and growth of individual cells in real−time. The platform can determine the growth rates of cells in just 10 minutes and map the growth of cell populations in short intervals. It can also identify differences in the growth of different subpopulations within a larger group. The platform was used to study the growth of MCF−7 cells and the impact of two intracellular metabolic processes on cell proliferation. The platform demonstrated the negative effect of serum starvation on cell growth and the role of a particular enzyme, ornithine decarboxylase (ODC), in cell proliferation. It was also able to show the ability of an external factor, putrescine, to rescue cells from the inhibitory effects of low osmolarity. In addition to measuring intracellular processes, the platform can determine the response of cancer cells to drug treatment. It showed the susceptibility of MCF−7 cells to a particular drug, difluoromethylornithine (DFMO), and the ability of a resistant subpopulation to survive in the presence of the drug. The platform’s ability to quickly measure cell growth in small samples makes it a potential tool for both research and clinical use.