Health & Fitness
Browse all 27 health & fitness tools
What is health and fitness calculators?
Health and fitness calculators use validated formulas — such as the Mifflin-St Jeor equation for calorie estimation and the US Navy method for body fat — to give you personalized metrics based on your body measurements and goals.
Basal Metabolic Rate (BMR) Calculator
Calculate BMR using 3 validated formulas. See daily calorie needs by activity level.
Blood Alcohol Calculator (BAC)
Estimate BAC using the Widmark formula. Enter drinks, weight, and hours to gauge impairment.
BMI Calculator
Calculate BMI and see your weight category. Includes healthy weight range for your height.
Body Fat Calculator
Calculate body fat percentage using the US Navy method with simple body measurements.
Calorie Calculator
Calculate daily calorie needs with BMR and TDEE. Get targets for weight loss, maintenance, or gain.
Gestational Age Calculator
Calculate gestational age from your LMP. See due date, trimester, and milestones.
Heart Rate Zone Calculator
Find your 5 heart rate training zones using age or resting HR. Supports Karvonen method.
Ideal Weight Calculator
Calculate your ideal weight using 4 formulas: Devine, Robinson, Miller, and Hamwi.
Intermittent Fasting Calculator
Calculate fasting and eating windows for 16:8, 18:6, 20:4, and OMAD protocols.
Keto Calculator
Calculate keto macros with net carb, fat, and protein targets based on your TDEE and goals.
Lean Body Mass Calculator
Calculate lean body mass using 3 scientific formulas from your weight and height.
Life Expectancy Calculator
Estimate life expectancy based on age, gender, smoking, exercise, and BMI factors.
Macro Calculator
Calculate daily protein, carb, and fat targets using TDEE and goal-based macro presets.
Medication Dosage Calculator
Calculate weight-based medication doses and liquid volumes using mg/kg formulas.
Menstrual Cycle Calculator
Predict next periods, fertile windows, and ovulation dates from your cycle length.
One Rep Max Calculator
Calculate your 1RM using 3 formulas and see a loading chart for rep ranges.
Ovulation Calculator
Find your ovulation day and fertile window from last period date and cycle length.
Pregnancy Due Date Calculator
Calculate your due date from LMP or conception. See week-by-week progress and milestones.
Protein Intake Calculator
Find your daily protein target in grams based on weight, activity, and fitness goal.
Running Pace Calculator
Calculate pace, finish time, or distance for any run. Projects 5K to marathon finish times.
Smoking Cost Calculator
Calculate the financial cost of smoking and see what you could save by quitting.
Sobriety Calculator
Track days sober, money saved, and recovery milestones on your sobriety journey.
Steps to Miles Calculator
Convert steps to miles, km, and calories burned using your height and weight.
TDEE Calculator
Calculate daily calories burned and recommended macros for your activity level and goals.
VO2 Max Calculator
Estimate VO2 Max from a run test, walk test, or resting heart rate. See fitness category.
Waist-to-Hip Ratio Calculator
Calculate your waist-to-hip ratio and see WHO health risk classification.
Water Intake Calculator
Calculate how much water you need daily based on weight, activity, and climate.
Formula & Methodology
Did you know? The BMI formula was invented by Belgian mathematician Adolphe Quetelet in the 1830s as a population-level statistical tool, not as a diagnostic measure for individuals — which is why many health professionals now complement it with body fat percentage and waist measurements.
Sources
- World Health Organization (WHO) — BMI classification and healthy weight guidelines
- National Institutes of Health (NIH) — Physical activity, calorie, and hydration recommendations