Damage characterization of a structure is a very significant aspect in failure analysis. Damage detection at an early stage prevents sudden failure of the structure, ensuring its uninterrupted functionality and reducing downtime. Various studies have been conducted over the past years to create structural health monitoring systems to replace traditional non-destructive inspection methods, which demand a lot of time delay, human labor, and expenditure. It has been demonstrated that vibration-based damage detection is best alternative method for assessing the intensity of the structure's damage. Present method utilizes modification in mode shapes to locate the damage in thin aluminum plate. Mode shape damage index (MSDI) assists to locate the damage with the aid of mode shape displacement magnitude. In order to determine the mode shapes of healthy as well as damaged plates, numerical and experimental modal analysis are performed. Three damage cases are considered with single and multiple crack slots. Due to the decrease in stiffness, there was a shift in the natural frequency plot of the healthy and damaged plate, indicating that there was damage. The presented approach was effective in detecting and locating the crack slots. The first and second mode shapes produced better results than the third mode when damage detection was performed on the first three mode shapes.