Now a days in modern industries and open channel very precise and accurate notches are used to measure the rate of flow for large and small flow. Notches are classified according to shape, in this experimental investigation different types of notches are used to measure the coefficient of discharge at different rate of flow. Experimental investigation shows that geometry of notches widely affect the discharge co-efficient. A notches of triangular (450 & 600) and rectangular are used in this investigation and compare the results of both to find the best notch.