Health Calculators & Converters

Monitor your wellness metrics with reliable health tools.

25 tools

About Health

Comprehensive health and fitness calculators for everyday wellness tracking — BMI, BMR, TDEE, body fat percentage, water intake, ideal weight, pregnancy due date, ovulation, blood pressure, BSA, and more. Each tool uses peer-reviewed medical formulas (Mifflin-St Jeor, Devine, Du Bois, Naegele's rule, etc.).

Whether you're tracking a weight-loss journey, planning meals around your daily calorie needs, monitoring blood pressure trends, or expecting a baby and need an accurate due date — these tools deliver clinical-grade calculations without the cost or wait of an appointment. Always confirm critical health decisions with a licensed doctor.

Clinically validated formulas

BMI (WHO), BMR (Mifflin-St Jeor 2005), pregnancy (Naegele's rule), body fat (US Navy method), and more.

Imperial + metric

All tools accept feet/inches, pounds, kilograms, and centimeters — switch units anytime mid-calculation.

Privacy-first

Your weight, age, body measurements, and pregnancy details never leave your browser.

Most Used

Most Popular in Health

The 4 tools our users open most often in this category.

4 picks

BMI Calculator

Calculate Body Mass Index and assess whether your weight is in a healthy range.

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BMR Calculator

Calculate your Basal Metabolic Rate — calories burned at rest.

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TDEE Calculator

Calculate Total Daily Energy Expenditure for weight loss, maintenance, or gain.

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Ideal Weight Calculator

Find your ideal weight range using multiple validated medical formulas.

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All Health Tools

Browse all 25 calculators

BMI Calculator

Calculate Body Mass Index and assess whether your weight is in a healthy range.

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BMR Calculator

Calculate your Basal Metabolic Rate — calories burned at rest.

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TDEE Calculator

Calculate Total Daily Energy Expenditure for weight loss, maintenance, or gain.

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Ideal Weight Calculator

Find your ideal weight range using multiple validated medical formulas.

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Water Intake Calculator

Calculate your recommended daily water intake based on weight and exercise.

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Body Fat Calculator

Estimate your body fat percentage using the US Navy measurement method.

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Macro Calculator

Calculate your daily protein, carbohydrate, and fat targets based on your goals.

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Pregnancy Due Date Calculator

Estimate your baby's due date based on your last menstrual period (LMP).

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Ovulation Calculator

Find your ovulation date and fertile window for conception planning.

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Heart Rate Zone Calculator

Calculate your max heart rate and five training zones for cardio workouts.

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Lean Body Mass Calculator

Estimate your lean body mass and body fat using medical formulas.

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Waist-to-Hip Ratio Calculator

Calculate waist-to-hip ratio — a strong predictor of cardiovascular risk.

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Calories Burned Calculator

Estimate calories burned for any activity using MET values and duration.

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Heat Index Calculator

Find the 'feels like' temperature from air temperature and humidity. Live weather for your country.

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Sleep Cycle Calculator

Find the best time to sleep or wake up based on 90-minute REM cycles — wake refreshed, not groggy.

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Pace Calculator (Running)

Convert finish time ↔ pace per km/mile + predicted finish times for 5K, 10K, half marathon, marathon.

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One-Rep Max (1RM) Calculator

Estimate your true one-rep max from any sub-maximal set using six published formulas (Epley, Brzycki, Lombardi, Lander, O'Conner, Wathen).

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Blood Pressure Category Checker

Classify your blood pressure per ACC/AHA 2017 (Normal, Elevated, Stage 1, Stage 2, Crisis) plus pulse pressure and MAP.

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Body Surface Area (BSA) Calculator

Compute Body Surface Area in m² using 5 published formulas (Mosteller, Du Bois, Haycock, Boyd, Gehan-George) — used in chemotherapy dosing and cardiac index.

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Protein Intake Calculator

Calculate daily protein needs for sedentary, active, fat-loss, muscle-gain, endurance, or elite-athlete goals. Includes food equivalents.

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Child BMI Percentile Calculator

Find your child's BMI percentile per CDC growth charts (ages 2–20). Accounts for age + sex — not just absolute BMI.

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Pregnancy Weight Gain Calculator

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Blood Alcohol Content (BAC) Calculator

Estimate blood alcohol content from drinks consumed using the Widmark formula. Time-decay adjustment + legal threshold reference.

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eGFR Calculator (Kidney Function)

Estimate Glomerular Filtration Rate using CKD-EPI 2021 (race-free) for adults. CKD stage classification + KDIGO reference.

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VO₂ Max Calculator

Estimate aerobic fitness (VO₂max) from resting heart rate, the 1-mile walk test, or the 12-minute Cooper run test.

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Frequently Asked Questions

Are these calculators medically accurate?

Yes — they use formulas published in peer-reviewed medical journals (the same formulas your doctor's software uses). However, they are screening tools, not diagnostic tools. Discuss any concerning result with a licensed physician.

Should I rely on a BMI calculator alone for weight assessment?

No. BMI is a quick screening metric but doesn't distinguish muscle from fat. Athletes and bodybuilders often have a 'high' BMI without being unhealthy. Combine BMI with body fat percentage and waist-hip ratio for a fuller picture.

How accurate is the pregnancy due date calculator?

Naegele's rule (LMP + 280 days) is accurate to within ±5 days for ~80% of pregnancies. Early ultrasound dating (6-9 weeks) is more accurate. The tool is for planning — every doctor visit will confirm or adjust based on ultrasound.

Is my health data shared anywhere?

No. All inputs (weight, age, body measurements, pregnancy dates) stay entirely in your browser. Nothing is transmitted to any server.