Free Fitness & Health Calculators
This collection of free fitness and health calculators is designed to provide clear, reliable estimates for common health metrics. Free to use in your browser.
Body & Nutrition
BMI Calculator
Calculate Body Mass Index and healthy weight range
BMR Calculator
Basal Metabolic Rate and daily energy expenditure
Calorie Calculator
Daily calorie needs with macro recommendations
TDEE Calculator
Total Daily Energy Expenditure for all activity levels
Body Fat Calculator
Body fat percentage using the US Navy Method
Ideal Weight Calculator
Ideal weight using 4 scientific formulas
Healthy Weight Calculator
WHO-based healthy weight range
Macro Calculator
Daily protein, carbs, and fat targets
Protein Intake Calculator
Daily protein needs based on goals
Carbohydrate Calculator
Daily carb intake by goal
Fat Intake Calculator
Daily fat needs
Water Intake Calculator
Daily hydration target
Fitness & Performance
Calories Burned Calculator
Calories burned by exercise type
Weight Loss Calculator
Calorie deficit planner with timeline
Pace Calculator
Running pace, time, and distance with splits
One Rep Max Calculator
Estimate 1RM using 7 scientific formulas
Lean Body Mass Calculator
Lean mass using Boer, James, and Hume formulas
Target Heart Rate
Exercise heart rate zones
Heart Rate Zone Calculator
Training heart rate zones
VO2 Max Calculator
Cardiovascular fitness estimate
Waist-to-Hip Ratio
WHR health assessment
Body Surface Area
BSA calculation
Sleep Calculator
Optimal sleep cycles
Why Trust These Calculators?
Our fitness and health calculators are built with accuracy, privacy, and simplicity in mind. Each tool uses established scientific formulas that have been validated through decades of research.
The BMI calculator uses the standard World Health Organization formula. Our BMR calculator implements the Mifflin-St Jeor equation, widely used as a more accurate estimator of resting metabolic rate than older equations. The body fat calculator uses the US Navy Method, which has been shown to correlate well with DEXA scans.
For pregnancy and fertility tools, we follow standard obstetric calculations based on Naegele's rule, with adjustments for cycle length and ultrasound dating.
Privacy-Conscious Approach
Calculations run in your browser. The values you enter stay on your device while you use the calculator, and the values you enter stay on your device while you use the calculator.
Free to Use
These tools are free to use. No premium tiers and no hidden fees. We build them because we believe everyone should have access to reliable health information.