Calorie Needs Calculator
Calculate exactly how many calories to eat daily to lose, maintain, or gain weight.
About Calorie Needs
Calorie needs depend on your BMR and activity level (TDEE). This calculator uses the Mifflin-St Jeor equation for BMR, then applies activity multipliers and adjusts for your weight goal.
Accuracy The Mifflin-St Jeor equation predicts BMR within ±10% for most adults and is the most validated formula in clinical use. The activity multiplier introduces additional variability — most people overestimate their activity level. Treat the result as a starting point and adjust by 100–200 kcal based on actual weight changes over 2–4 weeks.
Macro Distribution
| Macro | % of Calories | Calories/gram |
|---|---|---|
| Protein | 30% | 4 kcal/g |
| Carbohydrates | 40% | 4 kcal/g |
| Fat | 30% | 9 kcal/g |
What to do with your result
- Log your food intake for 2–4 weeks using the calorie target as your goal, then adjust ±100–200 kcal based on whether your weight is trending in the right direction.
- Prioritize hitting your protein target first (see Protein Intake calculator), then fill remaining calories with carbs and fats.
- If choosing 'Sedentary' feels too aggressive, try 'Lightly Active' — most people burn more than pure sedentary estimates suggest.
- Avoid dropping below 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision to protect muscle mass and nutrient intake.
Frequently Asked Questions
How many calories do I need to lose weight?
To lose approximately 0.5 kg (1 lb) per week, you need a calorie deficit of about 500 kcal per day. To lose 1 kg (2 lbs) per week, a 1,000 kcal daily deficit is needed. However, going below 1,200 kcal/day for women or 1,500 kcal/day for men is generally not recommended without medical supervision, as it can cause nutrient deficiencies and muscle loss.
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain basic functions like breathing, circulation, and cell repair. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor — the total calories you burn in a day including all physical activity. You should eat at or around your TDEE to maintain weight.
Why does the Mifflin-St Jeor formula use height and weight?
The Mifflin-St Jeor equation (the most validated BMR formula) uses sex, age, height, and weight because all four factors significantly influence metabolic rate. Taller and heavier people have more tissue to maintain, increasing BMR. Men typically have higher BMR than women due to greater muscle mass. The formula calculates BMR within about ±10% for most adults.
How accurate are online calorie calculators?
Calorie calculators based on validated formulas like Mifflin-St Jeor are accurate within ±10–15% for most people. The largest source of error is the activity multiplier — people tend to overestimate their activity level. Start with 'Sedentary' or 'Lightly Active' as a conservative baseline, then adjust based on 2–4 weeks of real-world results (weight trend, energy levels).
Should calorie intake change if I am strength training?
Yes. Strength training increases TDEE (calories burned) and also increases muscle mass over time, which raises your BMR. When building muscle, a modest calorie surplus of 250–500 kcal above TDEE combined with adequate protein (1.6–2.2 g/kg) is ideal. During a cut, keep protein high (2.0–2.4 g/kg) while in a moderate deficit to preserve muscle mass.
This calculator is for educational purposes only. Consult a qualified healthcare professional for medical advice.