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🥗 Calorie Calculator

Calculate your daily calorie target for weight loss, maintenance, or muscle gain using the Mifflin-St Jeor equation.

Enter Your Values

Your body weight in kg
Your height in cm
Your age in years

How to Calculate Your Daily Calorie Needs

This calculator uses the Mifflin-St Jeor equation, the most widely validated formula for estimating Basal Metabolic Rate (BMR) in modern clinical and research settings. The Mifflin-St Jeor equation calculates the calories your body burns at complete rest, then multiplies by an activity factor to give your Total Daily Energy Expenditure (TDEE) — the total calories you actually burn in a day including all activity.

The formula is: BMR (men) = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5. BMR (women) = 10 × weight + 6.25 × height − 5 × age − 161. This BMR is then multiplied by your activity level: sedentary (×1.2), lightly active (×1.375), moderately active (×1.55), very active (×1.725), or extremely active (×1.9).

For weight loss, eating 500 calories below your TDEE produces a deficit of approximately 3,500 calories per week, which corresponds to roughly 0.5 kg of fat loss per week — a clinically recognised sustainable rate. More aggressive deficits (750–1,000 calories below TDEE) can produce faster results but increase the risk of muscle loss, nutrient deficiency, and rebound weight gain if not maintained with sufficient protein intake.

For muscle gain, eating 250–500 calories above TDEE — a "clean bulk" — supports muscle growth with minimal fat gain when combined with progressive resistance training. A more aggressive surplus produces faster scale results but also more fat accumulation, which has to be dieted off later.

Individual variation is real. These formulas produce estimates, not exact figures. Factors like gut microbiome, hormonal variations, medication, and sleep quality affect actual calorie burn in ways that can't be captured in a simple formula. Treat the output as a starting point, track your weight for 2–3 weeks, and adjust intake up or down based on observed results.

How to Calculate Daily Calorie Needs

Your daily calorie requirement depends on your Basal Metabolic Rate (BMR) — the energy your body needs at rest — multiplied by an activity factor. This total is called TDEE (Total Daily Energy Expenditure) and represents the calories needed to maintain your current weight.

To lose weight, consume roughly 500 calories below TDEE per day for approximately 0.5kg (1lb) of loss per week. To gain weight, consume 300-500 calories above TDEE. Extreme deficits below 1,200 calories for women or 1,500 for men are generally not sustainable or recommended without medical supervision.

Frequently Asked Questions

How many calories do I need per day? +
Most adults need between 1,600-2,400 calories to maintain weight, depending on size and activity level. Sedentary small women may need 1,600-1,800; active large men may need 2,600-3,200. This calculator gives you a personalised estimate based on your measurements and activity.
Does eating less always cause weight loss? +
A calorie deficit causes weight loss, but severe restriction triggers muscle loss and metabolic adaptation, making long-term results harder to maintain. A moderate deficit of 300-500 calories per day, combined with adequate protein and strength training, produces better body composition outcomes than crash dieting.
Are all calories equal for weight loss? +
For pure weight (scale number), yes — a calorie is a unit of energy. For body composition, hunger management, and long-term health, no. Protein calories support muscle retention and satiety better than equivalent carbohydrate or fat calories. Food quality matters even when calories are matched.