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Health

Calorie Calculator.

Find your daily calorie target for weight loss, maintenance, or muscle gain based on your body stats and activity level.

Daily Target

kcal / day

BMR (at rest)

kcal

Maintenance

kcal (TDEE)

Protein

30% of cals

Carbs

40% of cals

Fat

30% of cals

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How Calorie Needs Are Calculated

Your daily calorie requirement depends on your resting metabolic rate (BMR), how active you are (TDEE), and your weight goal. This calculator uses the Mifflin-St Jeor equation — the formula validated by the Academy of Nutrition and Dietetics as the most accurate for modern adults.

Mifflin-St Jeor Equation

Men: BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5
Women: BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161
TDEE = BMR × Activity Factor
Target = TDEE ± Goal Adjustment

Calorie Adjustments by Goal

Weight Loss

1 lb of body fat ≈ 3,500 calories. A 500-calorie daily deficit produces roughly 1 lb/week of fat loss. A 250-calorie deficit (0.5 lb/week) is more sustainable and better preserves muscle. Avoid deficits over 1,000 calories/day without medical supervision.

Muscle Gain

A 250–500 calorie daily surplus supports lean muscle growth when combined with resistance training. Protein intake of 1.6–2.2g/kg of bodyweight is essential during a building phase. Exceeding 500 calories above TDEE tends to increase fat accumulation alongside muscle.

Knowledge Base

Daily Calorie Intake: Formula and How to Use It Methodology.

Your daily calorie target is determined by three factors: resting metabolism (BMR), activity level (TDEE), and weight goal (surplus or deficit). Getting this number right is the foundation of any sustainable diet plan for fat loss, maintenance, or muscle building.

The Calculation Branch

Men BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5 | Women BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161 | TDEE = BMR × activity factor | Lose 1 lb/week = TDEE − 500 | Gain 1 lb/week = TDEE + 500

Industrial Standards.

The Mifflin-St Jeor equation (1990) outperforms the older Harris-Benedict formula in clinical accuracy. A 2005 study in the Journal of the American Dietetic Association confirmed it is the most accurate predictor of resting metabolic rate for most adults. Activity multipliers: Sedentary 1.2, Light 1.375, Moderate 1.55, Active 1.725, Extra Active 1.9.

In-Depth Analysis & Reference Data

The macro split of 30% protein / 40% carbs / 30% fat is a balanced general-purpose starting point. Each gram of protein and carbohydrate provides 4 kcal; each gram of fat provides 9 kcal. Athletes and bodybuilders often push protein to 35–40% of calories and lower carbs accordingly. For weight loss, higher protein (35%+) preserves muscle mass during a calorie deficit.

Registry Questions & FAQ.

Why am I not losing weight at a 500-calorie deficit?

Common causes: inaccurate food tracking (underestimating portions), overestimated activity level, metabolic adaptation, or water retention masking fat loss. Weigh food with a scale rather than estimating by volume, and allow 4–6 weeks before adjusting your target.

Should I eat back exercise calories?

If your chosen activity level already includes your exercise (e.g., Very Active), do not eat back exercise calories — they are already factored in. If you selected Sedentary and exercise separately, eating back 50–75% of exercise calories is a reasonable adjustment.

All metrics verified against ISO/ASTM benchmarks.