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Popular Tools
BMI Calculator
Calculate your Body Mass Index (BMI) using height and weight. Understand your BMI category and what it means for your health.
Open toolTDEE Calculator
Calculate your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation. Find out how many calories you burn per day based on your activity level.
Open toolIdeal Weight
Calculate your ideal body weight using multiple formulas (Devine, Robinson, Miller, Hamwi). Find a healthy weight range based on your height and sex.
Open toolBody Fat Calculator
Calculate your body fat percentage using the U.S. Navy method. Enter your measurements to estimate body fat and understand your fitness category.
Open toolAll Tools
14 free calculators and health tools
BMI Calculator
Calculate your Body Mass Index (BMI) using height and weight. Understand your BMI category and what it means for your health.
Ideal Weight
Calculate your ideal body weight using multiple formulas (Devine, Robinson, Miller, Hamwi). Find a healthy weight range based on your height and sex.
Body Fat Calculator
Calculate your body fat percentage using the U.S. Navy method. Enter your measurements to estimate body fat and understand your fitness category.
Waist-to-Hip Ratio
Calculate your waist-to-hip ratio (WHR) to assess cardiovascular disease risk. A simple measurement used by the WHO as a health indicator.
BSA Calculator
Calculate your body surface area using Du Bois, Mosteller, and Haycock formulas. BSA is used in clinical medicine for drug dosing and medical calculations.
TDEE Calculator
Calculate your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation. Find out how many calories you burn per day based on your activity level.
Macro Calculator
Calculate your daily macronutrient needs (protein, carbs, fat) based on your TDEE and fitness goals. Get a balanced split for maintenance, cutting, or bulking.
Water Intake
Calculate your recommended daily water intake based on body weight and activity level. Stay properly hydrated with personalized recommendations.
eGFR Calculator
Calculate estimated glomerular filtration rate (eGFR) using the CKD-EPI 2021 equation. Assess kidney function and CKD staging from serum creatinine.
Creatinine Clearance
Calculate creatinine clearance (CrCl) using the Cockcroft-Gault equation. Used for renal drug dosing adjustments based on kidney function.
QTc Calculator
Calculate corrected QT interval using Bazett, Fridericia, and Framingham formulas. Assess QT prolongation risk from ECG measurements.
1RM Calculator
Calculate your estimated one-rep max using Epley, Brzycki, and Lander formulas. Determine your maximum strength from submaximal lifts.
Heart Rate Zones
Calculate your personal heart rate training zones using the Karvonen method. Optimize your cardio training with zones based on age and resting heart rate.
VO2 Max Estimator
Estimate your VO2 max from resting heart rate using the Uth method. Assess your cardiorespiratory fitness level and aerobic capacity.
Did You Know?
Your body is about 60% water. Even mild dehydration (1-2%) can impair cognitive performance and mood.
Try Water Intake CalculatorBMI was invented in the 1830s by a mathematician, not a physician. It was never intended as an individual health measure.
Try BMI CalculatorYour resting heart rate is one of the simplest indicators of cardiovascular fitness. Elite athletes can have a resting HR below 40 bpm.
Try Heart Rate ZonesThe kidneys filter about 180 liters of blood every day — that's enough to fill a bathtub twice over.
Try eGFR CalculatorFrequently Asked Questions
How do these calculators work?
Each tool uses peer-reviewed medical formulas (like Mifflin-St Jeor for TDEE or CKD-EPI for eGFR). You enter your measurements, and the calculation runs instantly in your browser — nothing is sent to a server.
Is my data stored anywhere?
No. All calculations happen entirely in your browser using JavaScript. We don't collect, store, or transmit any health data you enter. Your information never leaves your device.
Can I use these tools for medical decisions?
These tools are for educational and informational purposes only. They are not a substitute for professional medical advice. Always consult a qualified healthcare provider before making health decisions.
Are the formulas accurate?
We use well-established formulas from published medical literature. Each tool page cites the specific formula used. However, all estimation formulas have margins of error and may not be accurate for every individual.
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No subscriptions, no paywalls. All tools are completely free to use.
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All calculations happen in your browser. We never store or transmit your health data.
Evidence-Based
Our formulas come from peer-reviewed medical literature with cited sources.