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Health & Fitness Tools
Free health and fitness calculators — BMI, BMR and TDEE, body fat, ideal weight, macros, running pace, heart-rate zones and more. Provided for general information only, not medical advice.
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BMR & TDEE Calculator
Estimate your daily calorie needs (BMR and TDEE) using the Mifflin-St Jeor equation.
◔%Body Fat Calculator
Estimate your body fat percentage using the US Navy circumference method.
⚖Ideal Weight Calculator
Estimate ideal body weight from height using the Devine, Robinson, Miller and Hamwi formulas.
💧Water Intake Calculator
Estimate your daily water needs in liters and cups from weight and exercise time.
🏃Running Pace Calculator
Calculate running pace, time or distance, with pace per km and per mile and speed.
❤Heart Rate Zones
Find your max heart rate and the five training zones from your age and resting rate.
🍷Blood Alcohol (BAC) Estimator
Estimate blood alcohol content from drinks, weight and time using the Widmark formula.
🏋One Rep Max Calculator
Estimate your one-rep max from a lift and see training percentages from 95% to 60%.
🍗Macro Calculator
Split your daily calories into grams of protein, carbs and fat from a ratio preset.
🔥Calories Burned Calculator
Estimate calories burned for an activity from its MET value, your weight and duration.
💪Lean Body Mass Calculator
Estimate lean body mass and fat mass from your height and weight using the Boer formula.
⊙Waist-to-Hip Ratio
Compute your waist-to-hip ratio and the matching WHO health-risk category.
👶Pregnancy Due Date
Estimate a due date from your last period using Naegele's rule, adjusted for cycle length.
🚭Smoking Cost Calculator
See how much smoking costs you per day, week, month, year and over ten years.
🌸Ovulation Calculator
Estimate your ovulation day and 6-day fertile window for the next three cycles.
🤰Pregnancy Week Calculator
Find your current pregnancy week, trimester and due date from LMP, conception or IVF transfer date.
🥩Protein Intake Calculator
Get a daily protein target in grams from your body weight, goal and meal count.
🥑Keto Macro Calculator
Calculate ketogenic-diet macros: calories, fat, protein and a net-carb cap from your stats.
🩸A1C to Glucose Converter
Convert HbA1c to estimated average glucose (mg/dL and mmol/L) and IFCC mmol/mol, both ways.
🩺Blood Pressure Category Checker
Classify a blood pressure reading under both the US ACC/AHA and European ESC/ESH tables.
📐Body Surface Area Calculator
Calculate body surface area (m²) with the Mosteller, Du Bois, Haycock and Gehan–George formulas.
🧒Child BMI Percentile Calculator
Find a child's BMI percentile and z-score for age and sex using the WHO 5–19 y growth reference.
📏Child Height Predictor
Predict a child's adult height from the parents' heights with the mid-parental (Tanner) method.
🏁Race Time Predictor
Predict 5K, 10K, half and full marathon finish times from one recent race using the Riegel formula.
🫁VO2 Max Calculator
Estimate VO2 max from a Cooper 12-minute run or from your resting and maximum heart rate.
⏲Intermittent Fasting Window Calculator
Get your exact eating and fasting windows for 16:8, 18:6, 20:4, OMAD or a custom protocol.
☕Caffeine Half-Life Calculator
See how much caffeine remains in your body hour by hour and when you'll drop under 100 mg.
🧍Waist-to-Height Ratio Calculator
Check your waist-to-height ratio against the 'keep your waist below half your height' health rule.