Body Composition
Strategy Resource Center

Estimate Total Daily Energy Expenditure, Basal Metabolic Rate (BMR), and maintenance calories using Mifflin-St Jeor BMR, refined with Katch-McArdle when body fat is available. TDEE is the starting foundation for all calorie planning, fat loss, and muscle gain strategy.

Calculate your Basal Metabolic Rate (BMR), which represents the energy your body requires to function at complete rest. Uses Mifflin-St Jeor or Katch-McArdle equations to establish your baseline metabolic floor.

Calculate daily calorie targets for fat loss (cutting at a moderate 15% deficit), lean bulk (8% surplus), aggressive bulk (15% surplus), or recomposition (98%). Moderate ranges optimize fat mobilization and muscle retention.

Calculate training day (high calorie) and rest day (low calorie) splits aligned with your weekly strategy. Helps support training performance while promoting fat loss.

Find the exact number of daily calories required to maintain your current body weight. Uses Mifflin-St Jeor and Katch-McArdle equations with activity level multipliers.

Calculate a safe and sustainable calorie deficit target for fat loss. Sizes a moderate deficit (typically 15-20% below maintenance) to protect lean muscle tissue.

Calculate a controlled calorie surplus target to support muscle growth (hypertrophy) while minimizing fat spillover.

Translate your body composition goals (cut, bulk, recomposition, or maintenance) into exact daily calorie targets.

Quantify your daily calorie needs representing your body's total energy expenditure (TDEE).

Calculate the daily calorie target required to lose weight. Size your deficit based on your weekly weight loss rate target.

Calculate daily calorie targets to gain weight. Tailored specifically for lean muscle growth and hypertrophy.

Estimate daily protein intake for muscle protein synthesis, fat loss, and lean mass retention. Based on ISSN guidelines: 1.6-2.2 g/kg body weight adjusted by goal. Higher end (2.2 g/kg) recommended during calorie deficit to prevent muscle catabolism.

Determine daily protein, fat, and carb targets aligned with calorie goals. Sets protein first (1.9 g/kg), dietary fat at 28% of calories, then allocates remaining calories to carbohydrates. Practical macro planning for body composition diet adherence.

Estimate body fat percentage using the US Navy Circumference Method. Widely used for its simplicity and reasonable accuracy compared to clinical standards. Requires waist and neck for men, and waist, hip, and neck for women.

Calculate your lean body mass, fat mass, fat-free share, and body composition proportions using your body weight and body fat percentage. Provides a complete compartmentalized snapshot of your physical structure.

Calculate Fat-Free Mass Index (FFMI) to quantify muscle mass relative to height. Uses raw FFMI with Kouri height normalization to correct tall-athlete skew. Provides body composition context beyond BMI for training and strategy planning.

Calculate Lean Body Mass (LBM) from body weight and body fat percentage. LBM = Weight × (1 - BF/100). Differentiates metabolic tissue from stored fat for body composition assessment, calorie targeting, and goal planning.

Calculate Body Mass Index (BMI) as a weight-to-height screening metric. Categorizes results into underweight, normal (18.5-24.9), overweight, and obese ranges. BMI is a population screening tool, not a body composition assessment.

Calculate Waist-to-Height Ratio (WHtR) as a central adiposity screening metric. A ratio of 0.50 or higher indicates increased cardiovascular risk. Often more predictive than BMI alone for health context and body composition planning.

Forecast timeline to reach target body weight using compounding metabolic decay rather than linear projection. Accounts for metabolic adaptation with conservative weekly rates: 0.75% for fat loss, 0.2-0.4% for muscle gain. Generates non-linear projection curves for realistic planning.

Display height-based reference weight range using healthy BMI parameters (18.5-24.9). Provides a flexible range accounting for skeletal frame variation — not a single prescriptive target. Context for body composition goal setting.

Calculate target body weight from current lean mass and desired body fat percentage. Formula: Target Weight = LBM / (1 - Target BF%). Assumes lean mass is held constant. Practical for setting body composition goals with your strategy.

Project realistic muscle gain using the Alan Aragon rate model. Beginners: 0.2% body weight per week. Intermediates: 0.1%. Advanced: 0.05%. Training age, program quality, and adherence strongly affect lean bulk outcomes and timelines.

Calculate calorie and protein targets for simultaneous fat loss and muscle gain. Near-maintenance calories (2% deficit) with higher protein emphasis (2.2 g/kg). Recomp progress is slower; judge results beyond scale weight using body composition trends.