Our Methodology

Formulas Used

This calculator uses three peer-reviewed BMR equations: **Mifflin-St Jeor** (1990), **Harris-Benedict (revised)** (1984), and **Katch-McArdle** (1996). Each BMR is multiplied by a standard physical activity level (PAL) factor to estimate TDEE.

Known Limitations

TDEE estimates can vary ±10–15% from actual expenditure. Factors like genetics, NEAT (non-exercise activity thermogenesis), hormonal status, and medication use are not captured. Use the result as a starting point and adjust based on real-world results over 2–4 weeks.

Citations

1. Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247.
2. Roza AM, Shizgal HM. The Harris Benedict equation reevaluated. Am J Clin Nutr. 1984;40(1):168-182.
3. McArdle WD, Katch FI, Katch VL. Exercise Physiology: Energy, Nutrition, and Human Performance. 5th ed. 2001.

Formulas Used

**BMI = weight (kg) ÷ height (m)²**. The formula was devised by Adolphe Quetelet in the 1830s and adopted by the WHO for population-level screening.

Known Limitations

BMI does not distinguish between muscle and fat mass. Athletes, pregnant women, the elderly, and highly muscular individuals may receive misleading results. BMI is a screening tool, not a diagnostic measure.

Citations

1. World Health Organization. Obesity and Overweight Fact Sheet. 2024.
2. WHO Expert Consultation. Appropriate body-mass index for Asian populations. Lancet. 2004;363(9403):157-163.

Formulas Used

Macro grams are derived from total calories: **Protein (g) = (calories × protein%) ÷ 4**, **Carbs (g) = (calories × carb%) ÷ 4**, **Fat (g) = (calories × fat%) ÷ 9**. Preset ratios are based on general sports-nutrition guidelines.

Known Limitations

Optimal macro ratios vary by individual and depend on factors like training volume, body composition, metabolic health, and food preferences. Use presets as starting points and adjust based on your response over 2–4 weeks. Consult a registered dietitian for medical nutrition therapy.

Citations

1. Jäger R, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
2. Helms ER, et al. Evidence-based recommendations for natural bodybuilding contest preparation. J Int Soc Sports Nutr. 2014;11:20.

Formulas Used

Uses the **Mifflin-St Jeor** equation to estimate BMR, then multiplies by a physical activity level factor. Weight-loss targets use a 500 kcal/day deficit (~0.45 kg/week); weight-gain targets use a 300 kcal/day surplus.

Known Limitations

Individual metabolism varies. These estimates should be treated as a starting point. Track your weight for 2–4 weeks and adjust intake by 100–200 kcal as needed.

Citations

1. Mifflin MD, St Jeor ST, et al. Am J Clin Nutr. 1990;51(2):241-247.
2. Hall KD, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826-837.

Formulas Used

**Navy Method (Men):** BF% = 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76. **Navy Method (Women):** BF% = 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387. **BMI Method (Men):** BF% = 1.20 × BMI + 0.23 × age − 16.2. **BMI Method (Women):** BF% = 1.20 × BMI + 0.23 × age − 5.4.

Known Limitations

Circumference-based estimates have a standard error of ±3–4%. Results are less reliable for individuals with unusual fat distribution patterns, very lean athletes, or the elderly. For clinical accuracy, consider DEXA scanning.

Citations

1. Hodgdon JA, Beckett MB. Prediction of percent body fat for U.S. Navy men and women from body circumferences and height. Naval Health Research Center, Report No. 84-29. 1984.
2. Deurenberg P, et al. Body mass index as a measure of body fatness. Br J Nutr. 1991;65(2):105-114.

Formulas Used

**Devine (1974):** Men = 50 + 2.3 × (height_in − 60) kg; Women = 45.5 + 2.3 × (height_in − 60) kg. **Robinson (1983):** Men = 52 + 1.9 × (height_in − 60); Women = 49 + 1.7 × (height_in − 60). **Miller (1983):** Men = 56.2 + 1.41 × (height_in − 60); Women = 53.1 + 1.36 × (height_in − 60). **Hamwi (1964):** Men = 48 + 2.7 × (height_in − 60); Women = 45.5 + 2.2 × (height_in − 60).

Known Limitations

These formulas were developed for clinical dosing and do not account for muscle mass, frame size, or ethnicity. They tend to underestimate for taller individuals and overestimate for shorter individuals. Use them as a reference range, not an absolute target.

Citations

1. Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm. 1974;8:650-655.
2. Robinson JD, et al. Determination of ideal body weight for drug dosage calculations. Am J Hosp Pharm. 1983;40(6):1016-1019.

Formulas Used

**Epley:** 1RM = w × (1 + r/30). **Brzycki:** 1RM = w × 36/(37 − r). **Lombardi:** 1RM = w × r^0.10. **Mayhew:** 1RM = 100w / (52.2 + 41.9 × e^(−0.055r)). **O'Conner:** 1RM = w × (1 + r/40). **Wathan:** 1RM = 100w / (48.8 + 53.8 × e^(−0.075r)).

Known Limitations

Accuracy decreases for rep counts above 10. Formulas assume standard barbell exercises; they may not translate directly to machine exercises or unusual movement patterns. Individual leverages and training experience affect results.

Citations

1. Epley B. Poundage Chart. Boyd Epley Workout. 1985.
2. Brzycki M. Strength testing — predicting a one-rep max from reps-to-fatigue. J Phys Educ Recreat Dance. 1993;64(1):88-90.
3. LeSuer DA, et al. The accuracy of prediction equations for estimating 1-RM performance. J Strength Cond Res. 1997;11(4):211-213.

Formulas Used

The tool estimates your TDEE using Mifflin-St Jeor, then calculates the daily deficit as TDEE − planned intake. Weekly weight loss is projected as (daily deficit × 7) ÷ 7,700 kcal/kg. The TDEE is recalculated as weight decreases (adaptive TDEE). A flag is raised if the deficit exceeds 1,000 kcal/day or intake falls below 1,200 kcal (women) / 1,500 kcal (men).

Known Limitations

Weight loss is non-linear in practice due to water retention, metabolic adaptation, and changes in activity. This projection assumes a static adherence rate and does not account for plateaus. Consider it a best-case estimate.

Citations

1. Hall KD, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826-837.
2. Thomas DM, et al. Can a weight loss of one pound a week be achieved with a 3500-kcal deficit? Commentary on a commonly accepted rule. Int J Obes. 2013;37(12):1611-1613.

Formulas Used

The calculator divides daily protein evenly across chosen meals, then checks that each portion falls within the optimal MPS range of 0.25–0.55 g/kg body weight. If not, it adjusts meal count or flags that total protein may be too low/high for the chosen meal frequency.

Known Limitations

The MPS thresholds are population averages and may differ for trained vs. untrained individuals, older adults, and those in a large calorie deficit. Protein quality (leucine content) also matters and is not captured here.

Citations

1. Schoenfeld BJ, Aragon AA. How much protein can the body use in a single meal for muscle-building? J Int Soc Sports Nutr. 2018;15:10.
2. Morton RW, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength. Br J Sports Med. 2018;52(6):376-384.