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● Methodology

Methodology

For each calculator, VitaMath shows the formula on the page and cites the source study directly below the result. This page collects all four formula sources in one place for reference.

BMI

BMI = weight (kg) ÷ height (m)²
  • Quetelet, A. (1832). Original index — Sur l'homme et le développement de ses facultés.
  • Keys, A. et al. (1972). Indices of relative weight and obesity. Journal of Chronic Diseases, 25(6), 329–343.
  • WHO classification (underweight / normal / overweight / obese) per current WHO global guidelines.

Body Fat %

VitaMath offers two methods:

  • U.S. Navy method— Hodgdon, J.A. & Beckett, M.B. (1984). Prediction of percent body fat for U.S. Navy men and women from body circumferences and height. NBDMED Technical Report 84-29. Naval Health Research Center.
  • Jackson-Pollock— Jackson, A.S. & Pollock, M.L. (1978). Generalized equations for predicting body density of men. British Journal of Nutrition, 40(3), 497–504.
  • Body fat categories reference ACSM (American College of Sports Medicine) guidelines.

TDEE

Three base metabolic rate formulas are available:

  • Mifflin-St Jeor — Mifflin, M.D. et al. (1990). A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 51(2), 241–247.
  • Harris-Benedict (revised)— Roza, A.M. & Shizgal, H.M. (1984). The Harris Benedict equation reevaluated. American Journal of Clinical Nutrition, 40(1), 168–182.
  • Katch-McArdle— Katch, F. & McArdle, W.D. (1996). Introduction to Nutrition, Exercise, and Health(4th ed.). Lea & Febiger. Uses lean body mass as input.

Activity multipliers (sedentary → extra active) follow ACSM guidelines.

One-Rep Max

1RM ≈ f(weight, reps) — four formulas averaged or shown individually
  • Epley — Epley, B. (1985). Poundage Chart. Boyd Epley Workout. University of Nebraska.
  • Brzycki — Brzycki, M. (1993). Strength testing — predicting a one-rep max from reps-to-fatigue. Journal of Physical Education, Recreation & Dance, 64(1), 88–90.
  • Wathan — Wathan, D. (1994). Load assignment. In T.R. Baechle (Ed.), NSCA Essentials of Strength Training and Conditioning (pp. 435–439). Human Kinetics.
  • Mayhew — Mayhew, J.L. et al. (1992). Relative muscular endurance performance as a predictor of bench press strength in college men and women. Journal of Sports Medicine and Physical Fitness, 32(1), 37–43.

Found an error?

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