TDEE & Daily Calorie Calculator

What Is TDEE?

TDEE (Total Daily Energy Expenditure) is the total number of calories you burn in a day. It accounts for your basal metabolic rate (BMR), physical activity, and the thermic effect of food. Eating below your TDEE creates a calorie deficit and causes weight loss; eating above it creates a surplus and causes weight gain; matching it maintains your current weight.

The Formula: Mifflin-St Jeor

This calculator uses the Mifflin-St Jeor equation, which has the strongest evidence base for accuracy across diverse populations. A 2005 meta-analysis found it outperforms the older Harris-Benedict formula for most age groups and body types.

Activity multipliers: Sedentary 1.2 · Lightly Active 1.375 · Moderately Active 1.55 · Very Active 1.725 · Extra Active 1.9

Calorie Deficit and Fat Loss

One kilogram of fat tissue stores approximately 7,700 kcal. A daily deficit of 500 kcal therefore produces ~0.5 kg of fat loss per week in theory — but fat loss is not perfectly linear because the body adapts metabolically. A 300–500 kcal daily deficit is the evidence-based sweet spot: fast enough to see progress, moderate enough to preserve muscle.

• Prioritise protein: During a deficit, consuming 1.8–2.2 g of protein per kg of body weight per day preserves lean mass (ISSN 2023 position stand).
• Add resistance training: People who diet without training lose 25–40% of their weight from muscle. Strength training reduces this dramatically.
• Track weekly averages: Daily weight fluctuates due to water, glycogen, and sodium. A 7-day rolling average is a far more reliable signal than any single weigh-in.

Calorie Surplus and Muscle Gain

Building muscle requires a slight calorie surplus to fuel protein synthesis. Large surpluses, however, are stored predominantly as fat. A lean bulk of +200–300 kcal per day optimises the muscle-to-fat gain ratio. Beginners can often gain muscle near calorie maintenance in the first few months ("newbie gains").

How to Distribute Your Macros

The macro split shown above (Protein 30%, Carbs 40%, Fat 30%) is a practical starting point. You can adjust it based on your goal:

• Fat loss: Raise protein to 35–40% of calories to preserve satiety and muscle.
• Endurance sports: Increase carbohydrates to 50–55% to fuel aerobic performance.
• Strength training: Prioritise protein; split remaining calories between carbs and fat based on preference.

Calories Are Only Half the Picture

Knowing your TDEE is a great first step — but training is what determines body composition. Two people in an identical deficit will have very different outcomes depending on whether they're lifting weights. Calorie tracking and workout tracking work best together.

This calculator is for informational purposes only and does not constitute medical or dietary advice. If you have a health condition, consult a physician or registered dietitian.