The exact number of calories that you should eat in a day depends both on your gender and also on your current height and weight. For example, if you are overweight and you are trying to lose some weight, then this obviously means that you will have to consume less calories. Based on your data that you provide (6 foot and 175 pounds), I have calculated your body mass index at 23.7 (assuming you are male). This puts you in the range of healthy weight for your height, so you shouldn't need to lose any weight. A BMI of greater than 25 would put you in the overweight category.
Assuming you don't need to lose any weight, then the amount of calories you should consume also will depend on your age (the older you are the less calories you need) and your activity level. If you are a professional athlete you will obviously need more calories than if you have a desk job!
One excellent approach would be to talk with your dietitian
. He or she will be able to assess your activity level and help you calculate how many calories you should be taking in.