Your daily calorie needs depend on two things: how many calories your body burns at rest (BMR) and how active you are (TDEE). Understanding these numbers helps you maintain, lose, or gain weight intentionally.
Basal Metabolic Rate (BMR)
BMR is the number of calories your body burns at complete rest to maintain basic life functions like breathing, circulation, and cell production. It is typically 60–70% of your total daily calorie burn.
The Harris-Benedict equation estimates BMR:
BMR = 10w + 6.25h − 5a + s
Where:
- w = weight in kg
- h = height in cm
- a = age in years
- s = +5 for males, −161 for females
Worked example: A 30-year-old male, 70 kg, 175 cm: BMR = 10(70) + 6.25(175) − 5(30) + 5 = 700 + 1093.75 − 150 + 5 = 1,648.75 kcal/day. Try it on the calorie calculator.
Total Daily Energy Expenditure (TDEE)
TDEE is your BMR multiplied by your activity level. This represents your actual daily calorie needs.
| Activity Level | Multiplier | Description |
|---|---|---|
| Sedentary | 1.2 | Desk job, little or no exercise |
| Lightly active | 1.375 | Light exercise 1–3 days/week |
| Moderately active | 1.55 | Moderate exercise 3–5 days/week |
| Very active | 1.725 | Hard exercise 6–7 days/week |
| Extra active | 1.9 | Very hard exercise, physical job |
Using the example above with moderate activity: TDEE = 1,648.75 × 1.55 ≈ 2,556 kcal/day.
Weight loss and gain
To lose weight, consume fewer calories than your TDEE. A deficit of about 500 calories per day leads to roughly 1 pound of weight loss per week. To gain weight, eat above your TDEE. Never eat below your BMR without medical advice.
One pound of body fat contains approximately 3,500 calories. Use the BMI calculator alongside calorie tracking for a complete health picture.
Limitations
The Harris-Benedict equation is an estimate. Individual metabolism varies due to genetics, body composition, hormones, and other factors. Use it as a starting point and adjust based on actual results over 2–4 weeks.
Frequently asked questions
How accurate is this calculator? This uses the Harris-Benedict equation, which is an estimate. Individual metabolism varies due to genetics, body composition, and other factors. Use this as a starting point and adjust based on your results.
How do I lose weight? To lose weight, you need to consume fewer calories than your TDEE. A deficit of about 500 calories per day leads to roughly 1 pound of weight loss per week.
What is the difference between BMR and TDEE? BMR is calories burned at complete rest. TDEE is BMR multiplied by your activity level, representing your actual daily calorie needs.
How many calories are in a pound of fat? One pound of body fat contains approximately 3,500 calories. To lose one pound per week, you need a deficit of about 500 calories per day.