Health Tools
Understand your body composition and metabolic health with our calculators based on formulas from the US Navy, WHO, and Karvonen.
Health and fitness calculators are only as useful as the formulas behind them. Every tool in this category uses peer-reviewed, clinically validated equations.
BMR/TDEE calculators use the Mifflin-St Jeor equation — the most accurate population-level resting metabolic rate formula, validated against indirect calorimetry in multiple independent studies. Results are within ±10% of measured values for 82% of adults.
Body fat calculators use the U.S. Navy circumference method, developed and validated by Hodgdon & Beckett (1984) for the Naval Health Research Center. This method achieves a standard error of approximately 3.5% body fat — comparable to bioelectrical impedance at a fraction of the cost.
Heart rate zone calculators implement the Karvonen formula (heart rate reserve method), which produces more individualized training zones than the simple percentage-of-MHR approach, particularly for athletes with unusually high or low resting heart rates.
Strength calculators implement four validated 1RM prediction equations (Epley, Brzycki, Lander, O'Conner) and display results from all four for comparison.
One Rep Max Calculator
Calculate your estimated 1RM (One Repetition Maximum) for squat, bench press, and deadlift based on your reps.
Vertical Jump Power Calculator
Estimate your vertical jump height and peak explosive power using the Sayers Formula.
Strength Standards Calculator
Compare your lifts against other lifters at your bodyweight. Are you a beginner, intermediate, or elite lifter?
Wilks Score Calculator
The standard formula used in powerlifting to compare strength across different bodyweights.
Relative Strength Calculator
Calculate your strength-to-weight ratio. Crucial for calisthenics, gymnastics, and rock climbing.
Heart Rate Zone Calculator (Karvonen)
Calculate your optimal target heart rate zones for fat burning and endurance training using the precise Karvonen formula.
BMR & TDEE Calculator
Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE). The first step to any weight loss plan.
BMI Calculator
Check your Body Mass Index (BMI) instantly. A simple screening tool for weight categories.
Body Fat Calculator (Navy Method)
Estimate your body fat percentage without calipers. Based on the accurate US Navy formula using tape measurements.
Waist-to-Hip Ratio Calculator
Assess your fat distribution pattern and health risks. Are you an "Apple" or a "Pear"?
Ideal Weight Calculator
Find your medically recommended healthy weight range based on height and gender.
VO2 Max Estimator (Cooper Test)
Estimate your VO2 Max and cardiovascular fitness level using the 12-Minute Run Test (Cooper Test).
Bench Press Calculator
Calculate your bench press one-rep max and get personalized training percentages for strength, hypertrophy, and power.
Squat Calculator
Calculate your squat one-rep max from any weight and rep combination. Includes strength standards and training percentages.
Deadlift Calculator
Calculate your deadlift one-rep max from any working set. Includes strength standards, technique cues, and training percentages.
Sleep Cycle Calculator
Find the best bedtime or wake-up time based on 90-minute sleep cycles to wake up refreshed and optimize athletic recovery.
Electrolyte Loss Calculator
Estimate sodium, potassium, and magnesium lost through sweat during exercise and calculate your electrolyte replacement needs.