Health Performance.
Bio-metric analytics tuned for athletes and health-conscious professionals. Determine accurate caloric burns and build custom macronutrient partitions based on verified physiological models.
FFMI Calculator
Fat-Free Mass Index, normalized FFMI, lean body mass, and muscular potential assessment.
Launch ToolWaist-to-Hip Ratio Calculator
Waist-to-hip ratio from your measurements, checked against the WHO risk thresholds for men and women.
Launch ToolVO2 Max Calculator
Estimate aerobic fitness from a 12-minute run or a 1-mile walk, compared against fitness norms.
Launch ToolOne Rep Max Calculator
Estimate your 1RM from any set across three published formulas, with a percentage table for every training rep range.
Launch ToolTarget Heart Rate Calculator
Maximum heart rate and all five training zones by age, using either percentage of max or the Karvonen reserve method.
Launch ToolBMI & BMR Lab
Calculate your Body Mass Index and Resting Metabolic Rate accurately. Predict caloric needs based on specific lifestyle activity multipliers.
Launch ToolMacro Partitioning
Breakdown daily calorie intake into optimal grams of Protein, Carbohydrates, and Fats according to standardized athletic ratios.
Launch ToolComposition Analysis
Professional estimation of body composition using the US Navy method. Differentiates between adipose tissue and functional lean mass.
Launch ToolExpenditure Architect
Map your Total Daily Energy Expenditure. Includes basal metabolic rate and physical activity multipliers for precise management.
Launch ToolShower vs Bath Cost
Compare the annual water and energy cost of showers versus baths. Find which saves more money and water for your household.
Launch ToolRunning Pace Calculator
Work out pace, time or distance from the other two, and see predicted finish times for 5K, 10K, half marathon and marathon.
Launch ToolHydration Monitor
Calculate your daily water intake requirement based on body weight, activity level, and climate. Results in liters, fl oz, and glasses.
Launch ToolIdeal Body Weight
Compare your ideal weight across four clinical formulas — Devine, Robinson, Miller, and Hamwi — based on your height and gender.
Launch ToolCalorie Calculator
Calculate your daily calorie target for weight loss, maintenance, or gain using the Mifflin-St Jeor equation and activity level.
Launch ToolProtein Calculator
Find your optimal daily protein target in grams based on bodyweight and goal — muscle gain, fat loss, athletic performance, or general health.
Launch ToolCalories Burned
Estimate calories burned for 20+ activities using MET values and your body weight. Covers walking, running, cycling, swimming, HIIT, and more.
Launch ToolChild BMI Calculator
Calculate BMI for children aged 2–20 using CDC growth chart percentiles. Returns weight category adjusted for age and sex.
Launch ToolLooking up a term?
BMI, BMR, TDEE, macros, caloric deficit, body fat percentage — all defined plainly.
Research & Notes.
In-depth articles on the math and logic behind our tools — written for people who want to understand the calculations, not just run them.
FFMI Explained: The Muscularity Metric BMI Cannot Measure
FFMI isolates lean mass from total weight, normalized to a standard height so people of different sizes can be compared. The catch: it is only as accurate as the body fat percentage used to calculate it.
Waist-to-Hip Ratio vs BMI: What the WHO Thresholds Actually Mean
BMI cannot see where fat is stored, only how much of it there is. Waist-to-hip ratio fills that gap, and several cohort studies have found it a stronger predictor of cardiovascular risk than BMI alone.
How Ovulation Calculators Actually Work: The Math Behind the Fertile Window
The "day 14" rule assumes a 28-day cycle and misleads everyone else. Here is why counting backward from your next period, using your luteal phase, is the more reliable method.