🏥 77 Calculators · 19 Topics · Updated April 2026
Health & Nutrition Calculators
Free health calculators for BMI, BMR, TDEE, calorie intake, macros, body composition, and more. Built on clinically validated formulas like Mifflin-St Jeor and WHO standards.
Understanding your body's numbers is the foundation of any health or fitness plan. Our health calculators use the same clinically validated formulas that doctors and dietitians rely on, Mifflin-St Jeor for basal metabolic rate, WHO categories for BMI, and evidence-based guidelines for macronutrient targets. No sign-up, no data stored.
Most Popular
BMI Calculator
Calculate your Body Mass Index (BMI) from height and weight. See where you fall on the BMI scale.
TDEE Calculator
Calculate your Total Daily Energy Expenditure, the total calories you burn each day including activity.
Calorie Intake Calculator
Calculate how many calories you should eat daily based on your goals, lose, maintain, or gain weight.
Macro Calculator
Calculate your daily macronutrient targets, protein, carbs, and fat, based on your goals.
Body Fat Percentage Calculator
Estimate your body fat percentage using the US Navy method based on body measurements.
Pregnancy Due Date Calculator
Calculate your estimated due date based on the first day of your last menstrual period.
Browse by Topic
Safety
2 calculatorsEstimate blood alcohol content based on drinks, weight, and time elapsed.
Medical
1 calculatorCheck blood type compatibility for donations and transfusions.
Body Metrics
6 calculatorsMeasure BMI, body fat percentage, ideal weight, lean body mass, and waist-to-hip ratio. These calculators give you a baseline for tracking progress.
BMI Calculator
Calculate your Body Mass Index (BMI) from height and weight. See where you fall on the BMI scale.
BMI Calculator for Children
Calculate BMI for children and teens (ages 2-20) using CDC growth charts and age-based percentiles.
Body Fat Percentage Calculator
Estimate your body fat percentage using the US Navy method based on body measurements.
Ideal Weight Calculator
Calculate your ideal body weight range based on height, frame size, and gender.
Lean Body Mass Calculator
Calculate your lean body mass (total weight minus body fat).
Waist-to-Hip Ratio Calculator
Calculate your waist-to-hip ratio, a key indicator of health risk related to body fat distribution.
Nutrition
18 calculatorsCalculate your BMR (calories at rest), TDEE (total daily burn), target calorie intake, and macronutrient splits for protein, carbs, and fat. Based on the Mifflin-St Jeor equation.
BMR Calculator
Calculate your Basal Metabolic Rate, the calories your body burns at complete rest.
Caffeine Calculator
Calculate your daily caffeine intake and see if you're within safe limits.
Calorie Intake Calculator
Calculate how many calories you should eat daily based on your goals, lose, maintain, or gain weight.
Macro Calculator
Calculate your daily macronutrient targets, protein, carbs, and fat, based on your goals.
Macro Ratio Calculator
Find the ideal protein, carb, and fat ratio for your specific fitness goal.
Protein Intake Calculator
Calculate your daily protein needs based on body weight, activity level, and fitness goals.
TDEE Calculator
Calculate your Total Daily Energy Expenditure, the total calories you burn each day including activity.
Vitamin D Calculator
Calculate your recommended vitamin D intake based on age, weight, and sun exposure.
Keto Macro Calculator
Calculate macros for a ketogenic diet based on your stats and goals.
Breastfeeding Calorie Calculator
Extra daily calories needed while nursing.
Caffeine Half-Life Calculator
Caffeine remaining in your system after hours.
Hydration Status Calculator
Urine color + weight loss dehydration check.
Macro Split Calculator
Grams of protein/carbs/fat at a calorie target.
Fasting Metabolic Rate Calculator
Estimated fasting calorie burn.
Alcohol BAC Decline Calculator
Hours for BAC to reach 0.
Daily Fiber Intake Calculator
Grams of fiber needed per day.
Daily Sodium Limit Calculator
mg sodium recommended per day.
Daily Added Sugar Limit Calculator
Max grams of added sugar daily.
Weight Management
4 calculatorsSet calorie targets for cutting, bulking, or body recomposition. Calculate the deficit or surplus needed to reach your goal weight.
Body Recomposition Calculator
Calculate calories for body recomposition, building muscle while losing fat simultaneously.
Bulking Calorie Calculator
Calculate how many calories you need to eat for a lean bulk to maximize muscle growth.
Calorie Deficit Calculator
Calculate the exact calorie deficit needed to reach your goal weight by a target date.
Cutting Calorie Calculator
Calculate optimal calories for a cut phase, lose fat while preserving muscle mass.
Fitness
1 calculatorCalculate target heart rate training zones based on age and maximum heart rate.
Pregnancy
5 calculatorsEstimate due dates using Naegele's Rule (280 days from LMP) and plan with IVF-specific calculations.
IVF Due Date Calculator
Calculate your due date after IVF based on egg retrieval or embryo transfer date.
Pregnancy Due Date Calculator
Calculate your estimated due date based on the first day of your last menstrual period.
APGAR Score Calculator
Newborn 1- and 5-minute scores.
Gestational Age Calculator
Weeks pregnant from LMP or ultrasound.
Pregnancy Weight Gain Target
Recommended weight gain based on pre-pregnancy BMI.
Fertility
1 calculatorEstimate ovulation timing and fertile window based on cycle length.
Wellness
1 calculatorCalculate optimal sleep timing based on 90-minute sleep cycles and daily water intake needs.
Hydration
2 calculatorsDetermine how much water you should drink daily based on weight, activity, and climate.
Cardio
10 calculatorsHeart Rate Zone Calculator
Calculate heart rate training zones based on max heart rate.
Target Heart Rate Calculator
Calculate target heart rate for exercise using Karvonen method.
VO2 Max Calculator
Max oxygen uptake from 1-mile walk test.
Maximum Heart Rate Calculator
Age-predicted max HR (Tanaka formula).
Lactate Threshold HR Estimator
Training-zone anchor for endurance athletes.
Sweat Rate Calculator
Fluid replacement needed per hour of exercise.
Resting Heart Rate Zone Calculator
Classify resting heart rate by fitness level.
Blood Pressure Category Calculator
ACC/AHA category from systolic/diastolic.
VO₂ Max Estimate Calculator
Estimated VO₂ max from 1.5-mile run time.
Running Heart Rate Zone Calculator
Zones 1-5 from max HR.
Lab Values
8 calculatorsBlood Sugar Converter
Convert blood glucose between mg/dL and mmol/L.
eGFR Kidney Function Calculator
Estimated glomerular filtration rate (CKD-EPI).
Creatinine Clearance (Cockcroft-Gault)
Renal function via Cockcroft-Gault equation.
Corrected Sodium Calculator
Adjust serum sodium for glucose level.
Corrected Calcium Calculator
Calcium corrected for serum albumin.
Anion Gap Calculator
Metabolic acidosis screen.
Absolute Neutrophil Count Calculator
ANC from CBC with differential.
MELD Score Calculator
Liver-disease severity for transplant list.
Cardiology
6 calculatorsQTc Interval Calculator
Corrected QT interval (Bazett).
CHADS-VASc Stroke Risk
Annual stroke risk in atrial fibrillation.
HAS-BLED Bleeding Risk
Annual major bleeding risk on anticoagulation.
Framingham 10-Year Risk
Coronary heart disease risk.
LDL Cholesterol Calculator
Friedewald LDL from lipid panel.
Mean Arterial Pressure Calculator
MAP from SBP and DBP.
Body Composition
2 calculatorsMedication
3 calculatorsReproductive Health
3 calculatorsMental Health
2 calculatorsWeight
1 calculatorSleep
1 calculatorFrequently Asked Questions
What formula is used for BMR?
We use the Mifflin-St Jeor equation, which is considered the most accurate BMR formula for most people. For men: (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5. For women: the same formula minus 161 instead of plus 5.
How do I use TDEE for weight loss?
Your TDEE (Total Daily Energy Expenditure) is how many calories you burn per day. To lose weight, eat 500 calories below your TDEE for about 1 pound per week of fat loss. To gain weight, eat 300-500 above. Start with the TDEE calculator, then use the Calorie Intake calculator to set your target.
Are these calculators a substitute for medical advice?
No. These calculators provide estimates based on standard formulas and population averages. Individual results vary based on genetics, medical conditions, medications, and other factors. Always consult a healthcare provider before making significant changes to your diet or exercise routine.