Health & Fitness Calculators
Achieve your fitness and wellness goals with science-backed health calculators. Calnora’s 22 health engines compute Body Mass Index (WHO standards), Mifflin-St Jeor TDEE caloric targets, US Navy body fat percentage, target cardiovascular training heart zones, pregnancy due dates, eGFR kidney filtration, and daily macronutrient allocations.
Available calculators in Health & Fitness (22)
BMI & Body Weight Category
Calculate Body Mass Index (BMI), prime index, and healthy weight range for adults and children.
BMR & Daily Calorie (TDEE)
Determine Basal Metabolic Rate and Total Daily Energy Expenditure based on activity levels.
Body Fat Percentage (US Navy)
Estimate body fat percentage and lean muscle mass using tape measurements (waist, neck, hip).
Ideal Body Weight Calculator
Compare ideal weight estimates using Devine, Robinson, Miller, and Hamwi medical formulas.
Target Heart Rate Zones
Calculate cardiovascular training zones (warm-up, fat burn, aerobic, anaerobic, peak VO2 max).
Daily Water Intake
Estimate recommended daily hydration in liters and ounces based on weight and workout intensity.
Macronutrient Split Calculator
Calculate optimal grams of protein, carbs, and fats for fat loss, maintenance, or muscle building.
Pregnancy Due Date
Estimated due date and gestational age from LMP using Naegele's rule.
Ovulation & Fertile Window
Estimated ovulation day, fertile window, and next period from cycle length.
Running Pace Calculator
Pace per km or mile plus projected half-marathon and marathon finish times.
One-Rep Max (1RM)
Estimated 1RM from weight and reps using Epley, Brzycki, and Lander.
Waist-to-Hip Ratio
WHR and WHO-style risk category from waist and hip circumference.
Blood Alcohol Content (BAC)
Estimate blood alcohol concentration and time until sober using the Widmark formula.
Calories Burned (MET Activity)
Estimate calories burned based on body weight, duration, and MET activity intensity.
Pregnancy Weight Gain Tracker
Healthy gestational weight gain curve based on pre-pregnancy BMI (IOM guidelines).
Menstrual Cycle & Fertile Window
Estimate next period start date and fertile ovulation window.
Body Surface Area (BSA)
Calculate body surface area in m² using Mosteller, DuBois, and Haycock formulas.
Lean Body Mass (LBM)
Estimate lean muscle mass and implied body fat percentage via Boer and Hume equations.
Weight Loss Timeline
Calculate days and weeks required to reach target body weight at a given daily calorie deficit.
Child Adult Height Predictor
Predict adult child height using mid-parental method based on parents' heights.
VO₂ Max Fitness Calculator
Estimate maximal oxygen uptake (VO₂ max) and cardio fitness from 12-minute run distance.
eGFR Kidney Function
Estimate glomerular filtration rate using the CKD-EPI 2021 race-free creatinine equation.
Frequently Asked Questions — Health & Fitness
Which formula is used for calculating BMR and TDEE?
We use the clinically validated Mifflin-St Jeor equation, adjusted for physical activity multipliers to determine Total Daily Energy Expenditure (TDEE).
Are Calnora health calculators intended for medical diagnosis?
Calnora health tools are intended strictly for educational and general wellness informational purposes and should not replace clinical medical advice from a certified physician.