A natural gas automatic shutoff system can analyze the flow rate of natural gas through a pipe. When an anomaly is detected, the device can prevent further flow of natural gas through the pipe and can automatically notify the homeowner or authorized monitor, such as through a cell phone application or other device. Additionally, the homeowner or authorized monitor can manually control and/or monitor the flow of gas through the pipe in real-time, such as through a cell phone application or other device. At least one exemplary embodiment uses a motorized ball valve to control the flow of gas, a flow meter to measure the rate of natural gas flow through the pipe, and a microcomputer to analyze the flow and send notifications to the homeowner or authorized monitor.