How many calories should I eat per day?

To lose weight, you have to burn more calories than you take in. That's the easy part. Figuring out what that number is, now that's the hard part. 

Your BMR tells you how many calories your body burns at complete rest. This means not getting up to pee, not typing on your iPhone, literally nothing. As if you were in a coma. 

Your BMR is useful because you know that you need at the very least, this amount of calories. You never ever ever want to eat less than this number, because your body will go into starvation mode where you store all your fat, and burn lean muscle mass. (Basically, you lose lean weight and gain fat. you get "skinny fat". Soft and squishy body type). Not good.

Now, what also needs taken into consideration when determining how many calories you need per day is how many calories your body burns in a day via general daily activity and exercise. It is incredibly difficult to determine the exact correct number of calories you personally burn in a day, because everyone's bodies burn at different rates. So, the BMR and "daily caloric needs" calculators are only estimates. 

Here are the calculators:

BMR calculator

Daily Caloric Needs Estimator (the amount of calories you need per day to maintain your current weight.)

The caloric needs estimator tells you how to MAINTAIN your current weight. So, to lose weight, your calorie intake for the day should be between those two numbers.

It is a challenge to eat enough calories so that your body won't be running on lean muscle fumes, but not too many calories which will cause your body store fat. There is a lot of trial and error involved, but you can get a good starting point by using the calculators, and knowing these two numbers (your BMR and your daily caloric intake) you can make adjustments to figure out what works for you.