Free Fitness & Health Calculators
Our free fitness and health calculators help you understand your body, track your health metrics, and make informed decisions about nutrition, exercise, and wellness. Built on medically validated formulas from the World Health Organization, Centers for Disease Control, and peer-reviewed research — these tools give you reliable reference numbers you can use to guide your health decisions.
All fitness & health calculators
BMI Calculator
BMI, WHO categories, healthy range, and gauge visualization
Try it freeCalorie Calculator
TDEE and daily targets using Mifflin-St Jeor and activity level
Try it freeBody Fat Calculator
U.S. Navy method with ACE categories and lean vs fat mass
Try it freeBMR Calculator
Basal metabolic rate with multiple validated formulas
Try it freeIdeal Weight Calculator
Hamwi, Devine, Robinson, Miller, and healthy BMI band side by side
Try it freePace Calculator
Pace, time, distance, splits, converter, and race finish estimator
Try it freePregnancy Calculator
Due date from LMP, ultrasound, IVF, or conception — milestones
Try it freePregnancy Conception Calculator
Conception window from due date, LMP, or ultrasound dating
Try it freeDue Date Calculator
EDD from last period, conception, ultrasound GA, or IVF transfer
Try it freeUnderstanding your health starts with the right numbers
Whether you want to lose weight, build muscle, understand a pregnancy timeline, track your running progress, or simply know if your weight is healthy for your height — the right calculation gives you an objective starting point. These calculators don't replace medical advice, but they give you the factual foundation to have informed conversations with healthcare providers and set realistic personal goals.
What our health calculators cover
Body composition
The BMI Calculator calculates your Body Mass Index using WHO classification tables for adults and CDC percentile charts for children. The Body Fat Calculator estimates your body fat percentage using the US Navy circumference method — significantly more accurate than BMI alone because it accounts for body shape. The Ideal Weight Calculator computes your ideal weight range using four established medical formulas side by side so you can see the full picture.
Nutrition and calories
The Calorie Calculator estimates how many calories you need each day based on your age, gender, height, weight, and activity level — using the Mifflin-St Jeor equation recommended by the American Dietetic Association. The BMR Calculator finds your Basal Metabolic Rate using three different validated formulas including the Katch-McArdle formula for athletes who know their body fat percentage.
Fitness and performance
The Pace Calculator handles running, walking, and cycling pace calculations — including a multipoint segment analyzer, pace converter between miles and kilometers, and finish time estimator for races in progress. Compare your performance against world record paces and understand aerobic vs anaerobic training zones.
Pregnancy and reproductive health
The Pregnancy Calculator estimates your complete pregnancy schedule from any starting point — due date, last period, conception date, ultrasound date, or IVF transfer date. The Due Date Calculator provides your estimated delivery date with multiple calculation methods. The Pregnancy Conception Calculator estimates when conception occurred based on your due date, last period, or ultrasound measurements.
Our health calculators are used by people beginning fitness journeys who need a baseline, athletes tracking body composition changes, pregnant women planning their pregnancy timeline, runners analyzing their training pace, and anyone who wants to understand their health metrics better. All health calculators use validated formulas from recognized medical authorities. These tools provide educational estimates — always consult a healthcare provider for medical decisions and diagnosis.