How to Use This Calculator
- Enter age, sex, height, and weight.
- Pick an honest activity level (most people overestimate ??when in doubt, drop one level).
- Optional: enter body-fat % to enable the Katch-McArdle formula, which uses lean mass and tends to be more accurate for muscular or low-body-fat individuals.
- The result shows BMR, TDEE, target calories for several goals, and a macro split.
BMR Formulas
Basal Metabolic Rate is the energy required at complete rest to keep basic biology running ??breathing, circulation, cell maintenance. Three formulas are common:
Mifflin-St Jeor produces lower (and more accurate) BMRs than Harris-Benedict for most modern populations.[1] Katch-McArdle is best for people who know their body fat percentage with reasonable accuracy.
TDEE = BMR 횞 Activity Multiplier
Total Daily Energy Expenditure adds the energy you burn from movement and exercise. The multipliers above are widely-used approximations:
- 1.2 ??Sedentary: desk job, almost no exercise.
- 1.375 ??Lightly active: 1?? days of light exercise per week.
- 1.55 ??Moderately active: 3?? days of moderate exercise.
- 1.725 ??Very active: 6?? days of intense exercise.
- 1.9 ??Extra active: physical job + daily training, or multiple sessions per day.
Goal Calories
A pound of fat is about 3,500 kcal; a kilogram is about 7,700 kcal. So a 500-kcal-per-day deficit is roughly 1 lb / week of fat loss on average; the body's response is non-linear and rarely exactly matches the prediction. Aggressive deficits (more than 20??5% below TDEE) usually trigger metabolic adaptation, muscle loss, and adherence problems.
Macros
The macro split shown follows a common starting point ??protein 25??0% of calories (1.6??.2 g/kg of body weight is the typical range for active people[2]), fat 25??0%, carbs the remainder. Adjust as needed:
- Higher protein if losing weight (preserves lean mass) or strength training.
- Higher carbs if doing endurance training.
- Higher fat if you prefer satiety from fat or follow a keto/low-carb approach.
Frequently Asked Questions
Why do online calculators disagree?
Different BMR formulas, different activity multipliers, and rounding all contribute. A spread of 짹150 kcal is normal.
Should I eat back exercise calories?
If you already chose an "active" multiplier, no ??exercise is already in the TDEE. If you used "Sedentary" and add workouts, then yes.
How long should I follow a target before adjusting?
2?? weeks. Daily weight fluctuates by 1?? kg from water/sodium/glycogen; the underlying trend takes time to emerge.
References
[1] Mifflin M.D. et al. (1990). "A new predictive equation for resting energy expenditure in healthy individuals." Am J Clin Nutr. [2] Phillips S.M. et al. (2016). "Dietary protein requirements and adaptive advantages in athletes." J Int Soc Sports Nutr.