It is vital to measure the concentration of gas quickly in many gas sensing applications. Predicting the steady-state response from the earlier transient response is the economical and viable solution in this regard. However, existing transient analysis approaches either need huge data and computationally intensive algorithms or are inefficient. Here, we described a method to reduce the measurement time of the concentration of CH4 with a chemiresistive gas sensor at room temperature (27 °C). The presented method considers the sensor’s response at two fixed time intervals after gas exposure and maps their pairing number to the gas concentration. The proposed method measures the gas concentration in just 30 s from the gas exposure time. As the proposed method can quickly measure gas concentrations, it can be employed in widespread applications where quick quantification of gas is necessary. © 2021 The Authors. Published by American Chemical Society.