A flexible magnetic assembly based flow rate measurement device or flow meter, and method of sensing flow rate of a fluid using a flow rate measurement device are disclosed. The device comprises three separable chambers such as, a basal chamber, a mid-chamber and a top chamber. The basal chamber with an inlet and an outlet, is incorporated with a main sensitive component i.e. flexible magnetic assembly along flow path of a fluid that enter from the inlet and exit from the outlet of the basal chamber. The mid-chamber comprises a magnetic sensor, placed over the flexible magnetic assembly is configured to sense the changes in magnetization value. The top chamber comprises a processor and a display unit, is configured to process, convert and display the magnetization value. Further, a method of fabricating flexible magnetic assembly for a flow rate measurement device is also disclosed.