Scientifically calculate your daily calorie needs (TDEE) and optimal macronutrient split for protein, fat, and carbohydrates. Based on Mifflin‑St Jeor equation, activity level, and personalized fitness goals. Used by dietitians, athletes, and health enthusiasts.
Macronutrients (protein, fats, carbohydrates) are the foundation of human metabolism. This calculator employs the Mifflin-St Jeor equation, recognized by the Academy of Nutrition and Dietetics as one of the most accurate resting metabolic rate (RMR) formulas. Your Total Daily Energy Expenditure (TDEE) is then adjusted based on activity level and goal (deficit for fat loss, surplus for muscle gain).
Mifflin-St Jeor Equation:
Male: BMR = (10 × weight kg) + (6.25 × height cm) - (5 × age) + 5
Female: BMR = (10 × weight kg) + (6.25 × height cm) - (5 × age) - 161
This tool is designed for generally healthy adults aged 18–60 with a BMI between 18.5 and 35. It is not intended for pregnant or breastfeeding women, competitive adolescent athletes, individuals with severe obesity (BMI > 40), or those with metabolic disorders (diabetes, chronic kidney disease, thyroid conditions). For clinical populations, please consult a registered dietitian or physician. The equations used may overestimate or underestimate needs in highly muscular or elderly individuals.
Protein supports muscle repair, enzyme function, and satiety. Our calculator adjusts protein based on goal: 1.6–2.0 g/kg for maintenance and muscle gain, and up to 2.2 g/kg for weight loss to preserve lean mass. Dietary fat (20-30% of total calories) is essential for hormone production and vitamin absorption. Carbohydrates fuel your brain and muscles – the remaining calories after protein and fat are allocated to carbs, ensuring flexibility for any dietary preference.
Multiple meta-analyses (including studies by Hall KD, 2017; Helms ER et al., 2014) confirm that individualized macronutrient targets improve adherence and body composition outcomes. The Mifflin-St Jeor equation demonstrates a mean error of less than 5% compared to indirect calorimetry in normal-weight and overweight adults (Frankenfield et al., 2005). Our activity multipliers follow the Harris-Benedict revision standards widely used in clinical sports nutrition. Recent references: Helms ER et al. (2014) J Int Soc Sports Nutr 11:20; Thomas DT et al. (2016) Med Sci Sports Exerc 48(3):543-68 (ACSM energy balance position stand).
| Equation | Best for | Limitations |
|---|---|---|
| Mifflin-St Jeor (1990) | General population, normal to overweight | Less accurate in extremely muscular or obese |
| Harris-Benedict (1919, revised) | Historical reference, older adults | Tends to overestimate by ~5-10% |
| Katch-McArdle | Lean, athletic individuals (requires body fat %) | Not suitable without body fat measurement |
Our calculator uses Mifflin-St Jeor due to its superior accuracy in modern validation studies.
Sarah, weight 78kg, height 168cm, moderately active, wanted fat loss without losing muscle. Our calculator recommended 1,850 kcal/day with 145g protein, 55g fat, and 200g carbs. Over 12 weeks, she lost 5.2kg body fat while maintaining lean mass, validating the high-protein approach. The pie chart visualization helped her understand meal composition at a glance.
? How we built this tool: Every formula and coefficient was cross-verified against the Dietary Reference Intakes (DRI) and position stands from the International Society of Sports Nutrition (ISSN). The protein, fat, and carbohydrate distributions reflect current consensus for body composition goals. Our code is open for review, and we update recommendations every 12 months based on new evidence.