Health & Fitness Calculators
Free Online Health and Fitness Tools
Calculate BMI, calories, body fat, macros, and more with our comprehensive health and fitness calculators. Get personalized results instantly.
BMI Calculator
Calculate your Body Mass Index
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Calories Burned Calculator
Calculate calories burned during exercise and daily activities
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Ovulation Calculator
Track your fertile window and predict ovulation dates
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Period Calculator
Track your menstrual cycle and predict future periods
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Due Date Calculator
Calculate pregnancy due date using LMP or ultrasound
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Target Heart Rate Calculator
Calculate target heart rate zones for exercise training
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One Rep Max Calculator
Calculate one rep max for weightlifting exercises
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Calorie Calculator
Calculate daily calorie needs
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Body Fat Calculator
Estimate your body fat percentage
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BMR Calculator
Calculate your Basal Metabolic Rate
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Macro Calculator
Calculate macronutrient requirements
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Ideal Weight Calculator
Find your ideal body weight
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Pregnancy Calculator
Track your pregnancy timeline
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Pace Calculator
Calculate running and walking pace
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Protein Calculator
Calculate daily protein requirements
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TDEE Calculator
Calculate Total Daily Energy Expenditure
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Pregnancy Conception Calculator
Estimate conception date from due date or last period
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Body Surface Area Calculator
Calculate BSA for medical dosing applications
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BAC Calculator
Estimate blood alcohol content based on drinks consumed
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Lean Body Mass Calculator
Calculate lean body mass from weight and body fat
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Army Body Fat Calculator
Calculate body fat using U.S. Army circumference method
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GFR Calculator
Calculate estimated GFR to assess kidney function
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Your Health & Fitness Toolkit
Understanding your body's metrics is the foundation of any successful health journey. Our calculators use formulas established by the World Health Organization (WHO), Centers for Disease Control (CDC), and American Heart Association. BMI classifications follow WHO international standards. Calorie and macro calculations use the Mifflin-St Jeor equation—recognized as the most accurate for estimating metabolic rate.
For body composition, we offer multiple validated methods including the U.S. Navy body fat formula and Jackson-Pollock equations. Pregnancy calculators follow American College of Obstetricians and Gynecologists (ACOG) guidelines. Each result includes context about what the numbers mean for your health, along with evidence-based recommendations. Remember: these tools provide estimates for educational purposes—always consult healthcare professionals for medical decisions.
WHO & CDC Standards
BMI, body fat, and health risk assessments use internationally recognized classification systems.
Mifflin-St Jeor Formula
Calorie and TDEE calculations use the most accurate metabolic rate equation validated by research.
Multiple Methods
Body fat and ideal weight calculators offer several validated formulas so you can compare results.
Actionable Guidance
Every result includes what it means for your health and evidence-based next steps.