1. Change in demand means change in demand due to the factors of demand other than price whereas Change in quantity demanded means change in the quantity purchased due to change in the price of a product .
2. Change in demand has no price effect whereas Change in quantity has price effect.
3. Change in demand implies a change in demand curve whereas Change in quantity does not
4. Change in demand will result in the shift in the demand curve whereas Change in quantity will result in movement of demand curve.