Calorie Calculator
Estimate daily calories to maintain, lose, or gain weight based on your goals and activity.
Maintenance Calories
calories/day to maintain your current weight
BMR
calories/day at complete rest
Daily Calories by Goal
| Goal | Calories/day | Weekly change |
|---|
How Daily Calorie Needs Are Calculated
Your daily calorie needs are estimated through a three-step chain. First, we calculate your Basal Metabolic Rate (BMR) — the energy your body burns at complete rest to keep vital functions running. Next, we multiply BMR by an activity factor to get your Total Daily Energy Expenditure (TDEE), which represents the calories you burn in a typical day including movement and exercise. Finally, we adjust TDEE up or down depending on whether your goal is to maintain, lose, or gain weight.
Step 1: BMR (Mifflin-St Jeor Equation)
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Step 2: TDEE (Activity Multipliers)
| Activity Level | Multiplier |
|---|---|
| Sedentary (little or no exercise) | BMR × 1.2 |
| Light (exercise 1-3 days/week) | BMR × 1.375 |
| Moderate (exercise 3-5 days/week) | BMR × 1.55 |
| Very active (exercise 6-7 days/week) | BMR × 1.725 |
| Extra active (hard exercise & physical job) | BMR × 1.9 |
Step 3: The 7,700 kcal ≈ 1 kg Fat Principle
Roughly 7,700 calories equal about 1 kilogram of body fat (around 3,500 calories per pound). To change your weight, you create a calorie deficit (eat less than TDEE) to lose fat, or a calorie surplus (eat more than TDEE) to gain weight. Spreading that energy gap over a week gives a predictable rate of change:
- A daily deficit of 250 calories ≈ 1,750/week ≈ 0.25 kg (0.5 lb) loss per week (mild weight loss).
- A daily deficit of 500 calories ≈ 3,500/week ≈ 0.5 kg (1 lb) loss per week (weight loss).
- A daily deficit of 1,000 calories ≈ 7,700/week ≈ 1 kg (2 lb) loss per week (extreme loss).
- A daily surplus of 250–500 calories supports a steady, mostly lean weight gain.
These figures are estimates. Real-world results vary because metabolism adapts to calorie restriction, activity levels fluctuate, and body composition (fat vs. muscle vs. water) shifts over time.
Minimum Safe Calorie Intake
Cutting calories too aggressively can backfire — it slows metabolism, causes muscle loss, and risks nutrient deficiencies. As a general guideline, daily intake should not drop below approximately 1,500 calories for men and 1,200 calories for women without medical supervision. If a weight-loss goal in the table above falls below that floor, it is flagged so you can choose a more gradual approach. Always consult a healthcare professional or registered dietitian before starting an aggressive calorie-restriction plan.
Note: This calculator provides estimates based on the Mifflin-St Jeor equation, one of the most accurate predictive formulas for resting energy expenditure. Individual calorie needs vary with genetics, body composition, hormones, and other factors. Use the results as a starting point and adjust based on real-world progress over several weeks.