This might help you.
You might want to try this calculator for your BMR (basal metabolic rate).
http://www.bmi-calculator.net/bmr-calculator/ to double check what you found online.
Your basal metabolic rate is the calories that you burn just by being alive, i.e. you are lying in bed all day doing nothing. Your total daily calorie needs are calculated by taking your BMR and multiplying it by the factor in the Harris Benedict Formula
Harris Benedict Formula
To determine your total daily calorie needs, multiply your BMR by the appropriate activity factor, as follows:
If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2
If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375
If you are moderatetely active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.55
If you are very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.725
If you are extra active (very hard exercise/sports & physical job or 2x training) : Calorie-Calculation = BMR x 1.9
Once you know the number of calories needed to maintain your weight, you can easily calculate the number of calories you need to eat in order to lose weight. A 500 calorie per day deficit would give you a one pound per week loss. That is realistic and doable over the long term. Remember that your body is very good at adapting itself so that what worked before may not work always. You have to trick it!
Good luck!