Calorie Calculator is based on the Mifflin - St Jeor equation because is the most accurate. To determine your daily calorie amount you need: Enter your current weight, age, height, and gender into the calculator. Do your best estimate of how much exercise you will be doing. The results will show how many calories you may eat in order to maintain, gain or lose weight. You don't need to adjust this depending on your exercise rate - that is factored into the equation. The maintenance value is the same as what some people call Total Daily Energy Expenditure.