Calorie Calculator
This calorie calculator estimates the number of calories you should eat each day to reach your weight goal. It first calculates your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation, then adjusts based on whether you want to lose, maintain, or gain weight.
Quick Answer
To lose weight, eat 500 calories below your TDEE for ~1 lb/week loss. To gain, eat 250–500 above it. Most adults need 1,600–3,000 calories per day.
These results are estimates based on general formulas and are not a substitute for professional medical advice. Consult a healthcare provider before making health decisions.
How the Formula Works
Calculate your BMR using the Mifflin-St Jeor equation.
Males: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 Females: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161Multiply BMR by your activity level to get your TDEE.
TDEE = BMR × Activity MultiplierApply a calorie adjustment based on your weight goal.
Mild deficit: −250 cal/day | Moderate deficit: −500 cal/day | Aggressive deficit: −750 cal/day Mild surplus: +250 cal/day | Moderate surplus: +500 cal/dayEstimate weekly weight change using the 3,500 calorie rule.
Weekly Change (lbs) = (Daily Adjustment × 7) ÷ 3,500
Methodology & Sources
Reviewed and updated March 28, 2026 · Prepared by GetHealthyCalculators Editorial Team
This calculator estimates maintenance calories from the Mifflin-St Jeor equation and standard activity multipliers, then applies a fixed deficit or surplus. It is intended for practical planning, not exact prediction of weekly scale changes.
References
- A new predictive equation for resting energy expenditure in healthy individuals · American Journal of Clinical Nutrition
- Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults · National Institutes of Health
Limitations
- The 3,500 calorie rule is a simplified estimate — actual weight change depends on metabolic adaptation over time.
- Individual metabolism varies based on genetics, hormones, sleep, and stress levels.
- Aggressive calorie deficits (over 750 cal/day) may not be sustainable and can affect energy, mood, and muscle mass.
- This calculator does not account for specific macronutrient needs or meal timing.
Frequently Asked Questions
How many calories should I eat to lose weight?
What is a calorie deficit?
Is a 500 calorie deficit safe?
How does activity level affect my calorie needs?
Should I eat back the calories I burn during exercise?
What should I do if my weight loss stalls?
How low is too low for calories?
Distribute your calories across protein, carbs, and fat
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