Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain basic functions — breathing, circulation, cell production. It's the minimum calories needed to survive.
Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor. It represents the total calories you burn per day including exercise and daily movement. Eating at TDEE maintains your current weight; eating below it causes weight loss.
How accurate is this calculator?
The Mifflin-St Jeor equation is considered the most accurate for most people, within around 10%. Individual metabolism varies based on muscle mass, hormones, age and other factors.
How fast is safe weight loss?
A deficit of 500 kcal/day produces approximately 0.45kg (1lb) per week loss — generally considered a safe, sustainable rate. Deficits above 1000 kcal/day are rarely advisable without medical supervision.