I'm 5'5, 27yrs old & i weigh 171.2 with no illness or other health issues. how many calories do i have to consume a day to lose weight?

Diet AND exercise: For weight loss and optimal health- you need a multi-pronged approach. Changing the diet will help, but you should also have an exercise program. I suggest weight training- as that will build muscle which then serves to 'burn' fat even when you're not working out. This is because of the increased metabolic demands of the muscle you've added. For the food changes -try soups before meals to eat less