Improving the sensing performance of chemiresistive gas sensors is largely material-centric, but further studies are needed to optimize the performance of electrode interfaces and interdigitated electrode structures (IDEs) geometry. Hence, we systematically optimize IDEs geometry (spacing between fingers (Sf), finger width (Wf) and number of fingers (Nf)) using methane (100 ppm) selective nanomaterial. This study provides some fascinating findings: Changing the dimensions of Sf/Wf to 50–300 μm/20–75 μm in a constant device area increased sensing response by 1.2/1.54 times, possibly due to increased grain-to-grain contacts in sensing material/potential barrier between electrode and sensing material. Moreover, changing Nf from 2 to 44 and from 44 to 74 resulted in a 2.42-fold improvement and a 3.91-fold decrease in the sensing response, respectively. It can attribute to changes in the base charge density because it affects the contribution of charge carriers due to methane gas adsorption. This research opens the door for fabricating low-power highly sensitive gas sensors that can also be integrated into the Internet of Things.