TDEE & Macro Calculator
Estimate your daily calorie needs (TDEE) and a suggested protein, carb and fat split based on your body stats, activity level and goal — using the Mifflin-St Jeor equation, the formula with the best validated accuracy for the general population.
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Fill in your details and press Calculate to see your BMR, TDEE and a suggested macro split.
How this calculator works
Your Basal Metabolic Rate (BMR) is calculated with the Mifflin-St Jeor equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age, +5 for men or −161 for women. This replaced the older Harris-Benedict equation in most clinical settings after validation studies found it more accurate across a wider range of body types.
TDEE multiplies BMR by an activity factor (1.2 for sedentary up to 1.9 for extremely active) to estimate total daily calories burned including movement and exercise. From there, a ~500 kcal deficit targets roughly 0.45kg (1lb) of fat loss per week, and a ~300 kcal surplus targets a moderate, mostly-lean weight gain.
This is an estimate, not a medical calculation — individual metabolism varies by 10% or more from population formulas. Use it as a starting point, track your actual weight trend over 2-3 weeks, and adjust calories up or down based on what really happens.
Frequently Asked Questions
What's the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the energy your body burns at complete rest — just to keep organs functioning. TDEE (Total Daily Energy Expenditure) adds your activity level on top of that, giving a realistic estimate of total calories burned per day.
Which formula does this calculator use?
The Mifflin-St Jeor equation, which multiple validation studies (including a widely-cited 2005 comparison of predictive equations by Frankenfield et al.) found to be the most accurate BMR formula for the general population, replacing the older Harris-Benedict equation in most clinical and fitness settings.
How accurate is this calculator?
It's a population-level estimate, typically within 10% of measured energy expenditure for most people — but individual metabolism varies. Treat the result as a starting point: track your weight for 2-3 weeks at the suggested calories and adjust up or down based on the actual trend.
Why does the macro split change with my goal?
Protein needs increase slightly during a calorie deficit (to protect muscle mass while losing fat), which is why the 'lose' goal uses a higher protein target per kilogram of bodyweight than 'maintain' or 'gain'. Fat is held at a consistent percentage of total calories for hormone health, and carbohydrates fill the remainder.
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