Unless you are trying to fine-tune your calorie intake for cutting or bulking purposes, I'm not sure that it matters what your actual BMR is. You can count calories each day and see how that affects your weight loss or gain, but realize that your daily ups and downs don't really mean much. You'd have to track your weight loss progress over weeks. And like evolution said, 3500 Cal = 1 pound (of fat), so if you eat 2000 Cal a day and are losing one pound a week, that means that over the course of a week, you have a Cal deficit of 3500 Cal, or 500 Cal a day. And then it follows that your body burns on average 2500 Cal a day. If you are looking to lose weight, while counting Calories can help you, I think what's even more important is just to find a diet that is nutrious and satisfying such that you can avoid snacking. I don't believe one needs to count Calories to lose weight. Rather, I think people just need to find a diet that nourishes them and fills them up without being too high in Calories. For instance, soda pop and sugary candy don't fill people up and provide no nourishment. On the other hand, eggs (which have an undeserved bad reputation) do fill you up, provide a lot of nutrients, and are, I think, quite tasty to most people.
