Health & Fitness Calculators

Free online health calculators for BMI, BMR, TDEE, calorie needs, body fat, ideal weight, and more. Track your fitness goals with instant, accurate results.

BMI Calculator Calculate your BMI (Body Mass Index) instantly. Know if you are underweight, normal, overweight, or obese. Includes A... BMR Calculator Calculate your Basal Metabolic Rate (BMR) using Mifflin-St Jeor formula. Find the minimum calories your body needs at... TDEE Calculator Calculate your TDEE (Total Daily Energy Expenditure) based on activity level. Find exact daily calories needed to mai... Water Intake Calculator Free online water intake calculator. Instant results, no signup. Heart Rate Zone Calculator Free online heart rate zone calculator. Instant results, no signup. Age Calculator Calculate your exact age in years, months, days, hours, and minutes from your date of birth. Find days until your nex... Calories Burned Calculator Free online calories burned calculator. Instant results, no signup. Sleep Cycle Calculator Free online sleep cycle calculator. Instant results, no signup. Macro Calculator Free online macro calculator. Instant results, no signup. Pregnancy Due Date Calculator Free online pregnancy due date calculator. Instant results, no signup. Body Fat Calculator Free online body fat calculator. Instant results, no signup. Ideal Weight Calculator Calculate your ideal body weight using Devine, Robinson, Miller, and Hamwi formulas. See the healthy weight range for... Ovulation Calculator Calculate your ovulation date and fertile window based on your menstrual cycle. Track the best days for conception or... Blood Pressure Calculator Check your blood pressure category — normal, elevated, Stage 1, or Stage 2 hypertension. Understand systolic and dias... Protein Intake Calculator Calculate your daily protein requirement based on body weight, activity level, and fitness goals — muscle gain, weigh... Intermittent Fasting Window Calculator Calculate your intermittent fasting eating and fasting windows. Plan 16:8, 18:6, 20:4, and OMAD schedules based on yo... Waist-to-Height Ratio Calculator Calculate your Waist-to-Height Ratio (WHtR) — a better predictor of cardiovascular risk than BMI. Check if your waist... Ideal Body Weight Calculator Calculate Ideal Body Weight using the Devine formula — the clinical standard for medication dosing and medical assess... Body Surface Area Calculator Calculate Body Surface Area using Mosteller, DuBois, and Haycock formulas. Used in chemotherapy dosing and clinical m... BAC Calculator Calculate your Blood Alcohol Concentration (BAC) based on drinks consumed, weight, gender, and time elapsed. Know whe... Vitamin & Mineral Calculator Check your daily vitamin and mineral requirements by age and gender. See recommended dietary allowances (RDA) for ess... Smoking Cost Calculator Calculate how much money you spend on smoking per month, year, and decade. See the investment potential of quitting a... Child Height Predictor Predict your child's adult height using the mid-parental height method. Uses parent heights and child's current growt... Diabetes Risk Calculator Assess your Type 2 diabetes risk based on age, BMI, family history, activity level, and waist circumference. Get a pe... Sleep Debt Calculator Calculate your accumulated sleep debt and recovery timeline. Know how much sleep you need to catch up and optimal rec... Anemia Risk Calculator Check if your hemoglobin level indicates anemia. Categorize severity — mild, moderate, or severe — based on WHO guide... Cholesterol Ratio Calculator Calculate your cholesterol ratios — Total/HDL, LDL/HDL, and Triglyceride/HDL. Understand your cardiovascular risk fro... Calorie Deficit Calculator Calculate the daily calorie deficit needed for your weight loss goal. See a safe timeline based on 0.5–1 kg per week ... One Rep Max Calculator Calculate your one-rep max (1RM) for any exercise using Epley, Brzycki, and Lander formulas. Plan training percentage... Running Pace Calculator Calculate running pace per km or mile from your race time. Get splits, equivalent paces across distances, and trainin... Body Recomposition Calculator Calculate macros for body recomposition — losing fat while building muscle simultaneously. Get calorie cycling recomm... VO2 Max Calculator Estimate your VO2 Max from a walking test, running time, or resting heart rate. Assess your cardiovascular fitness le... Lean Body Mass Calculator Calculate your lean body mass (LBM) — total weight minus body fat. Uses Boer, James, and Hume formulas for estimation... Calorie Goal Calculator Calculate daily calorie targets for your specific goal — weight loss, muscle gain, maintenance, or lean bulk. Persona... Electrolyte Calculator Calculate daily electrolyte needs — sodium, potassium, and magnesium — based on activity, diet, and climate for optim...

How to use these calculators well

Health and fitness calculators are most useful when they give you a starting range, not a diagnosis. Use them to understand patterns, compare scenarios, and prepare better questions for a qualified professional.

  • Read the limitations section before using any BMI, calorie, or body-composition result in isolation.
  • Use consistent units and realistic activity levels to avoid false precision.
  • For pregnancy, blood pressure, diabetes risk, or other medical topics, treat the output as informational and verify with a clinician.

How we review this category

Health calculators are built around established public formulas and research-backed methods, then checked with worked examples and plain-language explanation. They are educational tools and do not replace medical care.

Related guides

BMI Chart India 2026: Are You in Healthy Range? TDEE Calculator: How Many Calories Do You Really Need? BMR Calculator: Understanding Your Resting Metabolism Sleep Calculator: Optimal Bedtime & Wake-Up Times

Editorial note: Read our Editorial Policy to see how Calc Labz validates formulas, examples, and updates.

Need a correction? Tell us here and include the calculator name, your inputs, and the issue you found.

About Our Health Calculators (37+ Free Tools)

Health monitoring through calculators is increasingly important as India faces a dual burden of malnutrition and lifestyle diseases. With 101 million diabetics and 315 million with hypertension, proactive health tracking is essential. Our health calculators use Asian-specific benchmarks where applicable — critical for South Asians who develop metabolic conditions at lower BMI levels. Tools cover body composition (BMI, body fat, lean mass, waist-hip ratio), nutrition (calories, macros, protein, water intake, calorie deficit), fitness (heart rate zones, VO2 max, one-rep max, running pace), and medical (pregnancy, ovulation, blood pressure, diabetes risk, sleep cycles).

What Sets Our Calculators Apart

  • ✅ Asian BMI cutoffs for South Asian accuracy
  • ✅ Clinically validated formulas (Mifflin-St Jeor, Karvonen)
  • ✅ Privacy-first: all health data stays on your device
  • ✅ Fitness + medical + nutrition tools combined
  • ✅ 100% free — no signup, no hidden costs
  • ✅ Works offline as a Progressive Web App
  • ✅ Mobile-friendly responsive design
  • ✅ Privacy-first: calculations run locally in your browser

Maintained by: Sagar Sahni, Calc Labz

Last updated: May 2026 · Total calculators: 37+

All calculators use validated formulas and are regularly updated. Results are for informational purposes — consult a professional for critical decisions.