Estimate your daily calorie needs using the Mifflin-St Jeor Equation.
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Estimates based on Mifflin-St Jeor Equation. Individual needs may vary.
A calorie is a unit of energy. In nutrition, calories refer to the energy people get from the food and drink they consume, and the energy they use in physical activity. Technically, one calorie is the amount of energy required to raise the temperature of one gram of water by one degree Celsius. The "calories" listed on food packages are actually kilocalories (1,000 times larger), but are commonly referred to simply as calories. Your body uses calories for everything from breathing and circulating blood to lifting weights and running marathons. Understanding calories is fundamental to managing body weight — consume more than you burn and you gain weight; burn more than you consume and you lose weight.
Your daily calorie needs depend on several factors including your age, gender, height, weight, and activity level. This calculator uses the Mifflin-St Jeor Equation, one of the most accurate formulas for estimating resting metabolic rate, combined with activity multipliers to determine your Total Daily Energy Expenditure (TDEE). From there, based on your goal — whether it's weight loss, maintenance, or weight gain — we calculate your target daily calorie intake.
Our calorie calculator follows a two-step process. First, we calculate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor Equation. Then, we multiply your BMR by an activity factor to get your Total Daily Energy Expenditure (TDEE). Finally, we adjust your TDEE based on your selected goal to arrive at your target daily calorie intake.
For Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
For Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Basal Metabolic Rate (BMR) is the number of calories your body requires to maintain basic physiological functions while at complete rest. This includes breathing, circulation, cell production, nutrient processing, and temperature regulation. BMR accounts for roughly 60–75% of your total daily calorie expenditure, making it the largest component of your energy needs. Factors that influence BMR include age (BMR decreases with age), gender (men typically have higher BMR due to more muscle mass), body composition (more muscle = higher BMR), genetics, and hormonal factors.
Total Daily Energy Expenditure (TDEE) represents the total number of calories your body burns in a 24-hour period. It is the sum of three components: BMR (60–75%), the thermic effect of food (about 10% — energy used to digest and process food), and physical activity (15–30%, which includes both exercise and non-exercise activity like walking, fidgeting, and standing). TDEE is the true measure of your daily calorie needs — if you eat exactly your TDEE in calories each day, your weight will remain stable.
To lose weight, you need to consume fewer calories than your TDEE — this is called a calorie deficit. A deficit of 500 calories per day typically leads to about 0.5 kg of fat loss per week, since one kilogram of body fat contains approximately 7,700 calories. For weight gain, you need a calorie surplus — consuming more than your TDEE. A surplus of 500 calories per day results in approximately 0.5 kg of weight gain per week. The quality of calories matters too: a diet rich in protein, fiber, and micronutrients supports overall health regardless of whether you're in a deficit or surplus.
Body Mass Index (BMI) is a measure of body fat based on height and weight. While it does not directly measure body fat, it provides a useful general indicator.
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obesity Class I (Moderate) |
| 35.0 – 39.9 | Obesity Class II (Severe) |
| 40.0 and above | Obesity Class III (Very Severe) |