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.
One 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.
Why the Mifflin-St Jeor Equation Replaced Harris-Benedict for Calorie Needs
For most of the 20th century, calorie calculators used a 1919 formula to estimate metabolic rate. A 1990 study showed it was overestimating BMR by 5% or more on modern populations. Here is why the replacement formula is more accurate.
BMI Is Flawed — Here's What Body Fat Percentage Tells You Instead
BMI classifies elite athletes as obese and misses metabolically unhealthy individuals with normal weight. Here is why body fat percentage is a more accurate health metric and how to calculate it.
How to Calculate Your Macros for Body Recomposition
Body recomposition — simultaneously losing fat and gaining muscle — requires specific macronutrient targets that differ from both bulking and cutting protocols. Here is the calculation.