Significant progress in nanoscience was achieved through the development of methods and instruments to better comprehend nanoscale properties. We present here a methodology and automated setup to measure layer-by-layer films capacitance in the air immediately after polyelectrolytes adsorption. It presents high accuracy (~0.01 pF) to check the capacitance stabilization during spontaneous drying process in the air, with sensitivity to show electrical signal alternation accordingly to the outermost polyelectrolyte layer. Besides, a linear trend in capacitance was observed similar to UV–vis measurements. This method allows analyzing films electrical properties, affording better choice of materials, thickness, and molecular architecture.