Health & Fitness Calculators
Calculate BMI, BMR, calories, body fat, heart rate and other health metrics.
Health metrics are useful when you know what they measure and what they ignore. Every calculator here states its formula (Mifflin-St Jeor for BMR, the standard BMI ratio, established zone percentages), a worked example, and its limits — including the population ranges each formula was derived from. Results are estimates to discuss with a clinician, not diagnoses.
BMI Calculator
Calculate Body Mass Index with category
BMR Calculator
Basal metabolic rate — 3 formulas: Mifflin-St Jeor, Harris-Benedict, Katch-McArdle
Calorie Calculator
Daily calorie needs (TDEE)
Body Fat Calculator
Estimate body fat percentage (Navy method)
Water Intake Calculator
Daily water requirement
Ideal Weight Calculator
Calculate ideal body weight (Devine)
Heart Rate Zone Calculator
Target heart rate zones for exercise
Pregnancy Due Date
Calculate pregnancy due date
Ovulation Calculator
Calculate ovulation date
Macronutrient Calculator
Calculate daily macros (protein/carbs/fat)
Lean Body Mass
Calculate lean body mass
Body Surface Area
Calculate body surface area (Mosteller)
Waist-to-Hip Ratio
Calculate WHR and health risk
VO2 Max Calculator
Estimate cardiovascular fitness
Pregnancy Weight Gain
Recommended pregnancy weight gain
Blood Pressure Category
Check blood pressure category
Calorie Burn Calculator
Calories burned by activity
Sleep Calculator
Calculate optimal sleep times
GFR Calculator
Estimate kidney function
Target Heart Rate Zones
Calculate your heart rate training zones
Sleep Quality Score
Calculate your sleep quality score based on duration and efficiency
Fatigue Score Calculator
Calculate your fatigue level based on sleep, activity, and stress
Navy Body Fat Calculator
Body fat % using the US Navy tape method
Calorie Deficit Calculator
Weight loss from a daily calorie deficit
Heart Rate Zones
Training zones from max heart rate
Ideal Body Weight
Ideal weight from multiple formulas
Fasting Timer Calculator
Intermittent fasting windows and stages
Sleep Debt Calculator
Accumulated sleep deficit and recovery
MET Value / Calories Burned
Calories burned from MET value
Body Type Calculator
Ectomorph/Mesomorph/Endomorph estimate
Iron Intake Calculator
Daily iron needs by age and gender
Vitamin D Dosage
Supplementation estimate to raise vitamin D level
Calorie Surplus/Deficit Goal
Daily calorie target for gain or loss
Burn Severity Calculator
Classify burns with the rule of nines (TBSA)
Drug Dosage Calculator
Weight-based medication dosage
Pregnancy Trimester Calculator
Trimester and due date from last menstrual period
Ovulation & Fertile Window
Estimate ovulation day and fertile window from cycle length
Cholesterol Ratio & LDL
TC/HDL ratio, non-HDL and Friedewald LDL from a lipid panel
Nap Planner & Sleep Cycles
Best nap times aligned to 90-minute sleep cycles
MAF Heart Rate (Aerobic Base)
Phil Maffetone 180-formula max aerobic heart rate
Health Insurance Cost Share
Deductible, coinsurance and out-of-pocket max
HbA1c to eAG Converter
Estimated average glucose from HbA1c percentage
Glycemic Load Calculator
GL from glycemic index and carbs per serving
Waist-to-Height Ratio Calculator
WHtR — a simple central obesity indicator
Mean Arterial Pressure Calculator
MAP from systolic and diastolic blood pressure
LDL Cholesterol Calculator
Friedewald LDL from total, HDL and triglycerides
IV Drip Rate Calculator
Drops per minute for IV infusions
Creatinine Clearance Calculator
Cockcroft-Gault estimate of kidney filtration
Formulas, worked examples aur edge cases ke liye: Health guides
Frequently asked questions
Why can BMI call a fit athlete "overweight"?
BMI only compares weight with height. Muscle is denser than fat, so a muscular person can carry a high BMI with low body fat. That is why BMI is useful for populations and rough screening, but should be read alongside a body-fat estimate and waist measurement for individuals.
Which metabolic-rate formula should I use?
Mifflin-St Jeor is the most widely used modern estimate and is generally closer for most adults than the older Harris-Benedict equation. Both are estimates from population data, so treat the result as a starting point and adjust it against what actually happens to your weight over a few weeks.
How accurate are heart-rate training zones?
Zone methods rely on an estimated maximum heart rate, and the common "220 minus age" rule can be off by 10-15 beats for an individual. Zones built on a measured maximum — or on heart-rate reserve — are noticeably better than ones built on the age estimate alone.
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