Calorie Calculator

The Calorie Calculator estimates daily calorie needs from age, sex, height, weight, activity level, and goal, combining Basal Metabolic Rate (BMR) with Total Daily Energy Expenditure (TDEE) to produce a maintenance calorie figure plus separate targets for weight loss and weight gain.

Results compare across activity levels, inputs are saved automatically for quick recalculation, and imperial or metric units both work directly. The output supports meal planning, energy tracking, and fitness or wellness goals with data-driven numbers.

• Estimate BMR to measure resting energy needs.
• Apply activity multipliers to calculate TDEE.
• Set a calorie target to maintain, lose, or gain weight.
• Convert between imperial and metric units automatically.
• Compare calorie needs across every activity level side by side.

This calculator estimates daily calorie needs using a two-step method grounded in the Harris-Benedict equation and adjusted for activity level. It reports how many calories the body requires each day to maintain, reduce, or increase weight.

BMR is the number of calories the body needs at rest to support essential functions such as breathing and blood circulation. It is calculated from age, sex, weight, and height:

• For males:
  BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) - (5.677 × age in years)
• For females:
  BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) - (4.330 × age in years)

Pounds and feet/inches convert to kilograms and centimeters automatically:

• Weight (kg) = pounds ÷ 2.2046
• Height (cm) = ((feet × 12) + inches) × 2.54

Total Daily Energy Expenditure (TDEE) reflects how many calories the body uses in a typical day, factoring in daily movement. It is calculated by multiplying BMR by an activity factor:

• Sedentary (Little or no activity): × 1.2
• Somewhat Active (Light activity): × 1.375
• Active (Moderate activity): × 1.55
• Very Active (High activity): × 1.725
• Intense (Extremely high activity): × 1.9

After TDEE is set, the calorie target shifts with the selected goal:

• Maintain Weight: Calorie needs = TDEE
• Lose Weight: Calorie needs = TDEE - 500, but not below BMR
• Gain Weight: Calorie needs = TDEE + 500

All calorie values are rounded to the nearest 50 for clarity and ease of use.

• Height: ((5 × 12) + 10) × 2.54 = 177.8 cm
• Weight: 160 ÷ 2.2046 = 72.57 kg
• 88.362 + (13.397 × 72.57) + (4.799 × 177.8) - (5.677 × 30) ≈ 1742
• TDEE: 1742 × 1.375 ≈ 2395, rounded to 2400 calories

• BMR: 447.593 + (9.247 × 60) + (3.098 × 165) - (4.330 × 25) ≈ 1406
• TDEE: 1406 × 1.55 ≈ 2179, rounded to 2200 calories
• Lose Weight: max(1406, 2200 - 500) = 1700 calories

• Maintenance Calories: the estimated TDEE, the level that holds weight steady.
• Weight Loss Target: a reduced calorie level that does not drop below BMR.
• Weight Gain Target: a higher calorie level to support gradual increase.
• Activity Breakdown: calories recalculated for every activity level, for side-by-side comparison.

How accurate is this calorie calculator? It uses the Harris-Benedict equations with standard activity multipliers. Results are practical estimates; individual needs vary based on body composition, metabolism, and health conditions.

What activity level should I choose? The right match is whichever option fits an average week: Sedentary suits desk jobs with little exercise, while Very Active or Intense suits frequent vigorous training or highly physical work.

How big should a calorie deficit be for weight loss? A typical starting point is about 500 calories below TDEE, aiming for gradual, sustainable loss while preserving energy and minimizing muscle loss.

Why do results round to the nearest 50? Rounding simplifies meal planning and tracking while keeping estimates useful, without changing the overall strategy.

Maintain Weight: matching intake to the maintenance calorie figure holds weight steady over time; tracking intake for two weeks against that target shows whether it needs adjusting up or down.

Lose Weight: the deficit target already respects BMR, so it never falls below resting energy needs. Pairing the deficit with adequate protein, hydration, and regular movement supports satiety and recovery.

Gain Weight: a steady surplus combined with progressive resistance training adds mass with less excess fat gain than a large surplus alone. Weekly weight and measurement checks confirm the pace stays gradual.

Maintenance Calories represent the daily energy budget that keeps weight stable. The Weight Loss and Weight Gain targets set a safe deficit or surplus around that budget, recalculated whenever weight, routine, or goals change. These figures work most reliably as a starting point, refined against weekly trends and how training and daily activity actually feel.

This tool is intended for informational and educational purposes only. It does not provide medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for any health-related concerns or decisions.