Tidal volume (VT) is defined as the volume of inhaled and exhaled air during normal breath, which is crucial for maintaining respiratory function, such as adequate air exchange in and out of the body. However, existing estimation methods either require complex setups or involve inconvenient and expensive devices, such as spirometer and chestband. Thus, leveraging the advanced artificial intelligence (AI) and wearable devices, we aim to develop a novel, accessible and convenient approach to estimate tidal volume. In this study, we propose the VTMonitor system, which utilizes consumer earbuds’ motion sensor data to estimate the tidal volume. We conducted two experiments, collecting data either in lab or at home. After analyzing the data, our VTMonitor system is effective in measuring the tidal volume.