Health & Fitness Calculators
Health, fitness, pregnancy, and nutrition calculators for wellness tracking
Health Calculators: BMI, Calories, Body Fat, Fertility & Pregnancy Tools
Quick, evidence-based health calculators for weight management, nutrition planning, body composition, and reproductive health. Use our free tools to estimate BMI, calorie needs, body fat percentage, ideal weight, protein targets, pregnancy due date, and ovulation windows.
Whether you want to lose weight safely, track daily calories, understand your body fat, or plan pregnancy dates, these calculators help you make faster decisions with reliable formulas and tailored results.
Quick note: These tools are designed for planning and education. They use validated formulas and industry-standard methods, but are not a substitute for professional medical guidance.
🔥 Most Popular Health Calculations
Quick access to the most searched health metrics:
BMI Calculations
Calorie Needs by Age & Gender
Pregnancy Due Date
Body Fat Percentage
Daily Protein Needs
Water Intake
📊 Health & Fitness Reference Tables
BMI Classification (WHO Standards)
| BMI Range | Category | Health Risk | Recommendation |
|---|---|---|---|
| Below 18.5 | Underweight | Malnutrition risk | Gain weight, consult doctor |
| 18.5 - 24.9 | Normal | Low risk | Maintain healthy lifestyle |
| 25.0 - 29.9 | Overweight | Moderate risk | Lose 5-10% body weight |
| 30.0 - 34.9 | Obese Class I | High risk | Lose 10-15% body weight |
| 35.0 - 39.9 | Obese Class II | Very high risk | Medical supervision needed |
| 40.0+ | Obese Class III | Extremely high | Immediate medical care |
Body Fat Percentage Reference
Men:
| Age | Essential | Athletes | Fitness | Average | Obese |
|---|---|---|---|---|---|
| 20-29 | 2-5% | 6-13% | 14-17% | 18-23% | 24%+ |
| 30-39 | 2-5% | 7-14% | 15-18% | 19-24% | 25%+ |
| 40-49 | 2-5% | 8-15% | 16-19% | 20-25% | 26%+ |
| 50+ | 2-5% | 9-16% | 17-20% | 21-26% | 27%+ |
Women:
| Age | Essential | Athletes | Fitness | Average | Obese |
|---|---|---|---|---|---|
| 20-29 | 10-13% | 14-20% | 21-24% | 25-30% | 31%+ |
| 30-39 | 10-13% | 15-21% | 22-25% | 26-31% | 32%+ |
| 40-49 | 10-13% | 16-22% | 23-26% | 27-32% | 33%+ |
| 50+ | 10-13% | 17-23% | 24-27% | 28-33% | 34%+ |
Daily Calorie Needs by Age & Activity Level
Men:
| Age | Sedentary | Moderate | Active |
|---|---|---|---|
| 18-25 | 2,400 | 2,800 | 3,200 |
| 26-35 | 2,400 | 2,600 | 3,000 |
| 36-45 | 2,200 | 2,600 | 2,800 |
| 46-55 | 2,200 | 2,400 | 2,800 |
| 56-65 | 2,000 | 2,400 | 2,600 |
| 66+ | 2,000 | 2,200 | 2,400 |
Women:
| Age | Sedentary | Moderate | Active |
|---|---|---|---|
| 18-25 | 1,800 | 2,200 | 2,400 |
| 26-35 | 1,800 | 2,000 | 2,400 |
| 36-45 | 1,800 | 2,000 | 2,200 |
| 46-55 | 1,600 | 2,000 | 2,200 |
| 56-65 | 1,600 | 1,800 | 2,000 |
| 66+ | 1,600 | 1,800 | 2,000 |
- Sedentary: Little to no exercise
- Moderate: Exercise 3-5 days/week
- Active: Exercise 6-7 days/week
Protein Requirements by Goal
| Body Weight | Sedentary | Moderate Activity | Muscle Building | Athletes |
|---|---|---|---|---|
| 50 kg | 40g | 60g | 100g | 125g |
| 60 kg | 48g | 72g | 120g | 150g |
| 70 kg | 56g | 84g | 140g | 175g |
| 80 kg | 64g | 96g | 160g | 200g |
| 90 kg | 72g | 108g | 180g | 225g |
| 100 kg | 80g | 120g | 200g | 250g |
- Sedentary: 0.8g per kg body weight
- Moderate: 1.2g per kg
- Muscle Building: 2.0g per kg
- Athletes: 2.5g per kg
Ideal Weight Ranges by Height
Men:
| Height | Small Frame | Medium Frame | Large Frame |
|---|---|---|---|
| 160 cm (5'3") | 51-55 kg | 54-59 kg | 57-64 kg |
| 165 cm (5'5") | 55-59 kg | 58-63 kg | 61-68 kg |
| 170 cm (5'7") | 59-64 kg | 62-68 kg | 66-73 kg |
| 175 cm (5'9") | 63-68 kg | 66-73 kg | 70-79 kg |
| 180 cm (5'11") | 68-73 kg | 71-79 kg | 75-84 kg |
| 185 cm (6'1") | 72-78 kg | 76-84 kg | 80-90 kg |
Women:
| Height | Small Frame | Medium Frame | Large Frame |
|---|---|---|---|
| 150 cm (4'11") | 42-46 kg | 44-50 kg | 48-55 kg |
| 155 cm (5'1") | 46-50 kg | 48-54 kg | 52-59 kg |
| 160 cm (5'3") | 50-54 kg | 52-58 kg | 56-63 kg |
| 165 cm (5'5") | 54-58 kg | 56-63 kg | 60-68 kg |
| 170 cm (5'7") | 58-63 kg | 61-68 kg | 65-73 kg |
| 175 cm (5'9") | 63-68 kg | 66-73 kg | 70-79 kg |
Water Intake Recommendations
| Body Weight | Sedentary | Moderate Activity | High Activity | Hot Climate |
|---|---|---|---|---|
| 50 kg | 1.5 L | 2.0 L | 2.5 L | 3.0 L |
| 60 kg | 1.8 L | 2.4 L | 3.0 L | 3.6 L |
| 70 kg | 2.1 L | 2.8 L | 3.5 L | 4.2 L |
| 80 kg | 2.4 L | 3.2 L | 4.0 L | 4.8 L |
| 90 kg | 2.7 L | 3.6 L | 4.5 L | 5.4 L |
| 100 kg | 3.0 L | 4.0 L | 5.0 L | 6.0 L |
- General Rule: 30-40 ml per kg body weight
- Add 500-750 ml for each hour of exercise
- Add 20-30% in hot/humid climates
Pregnancy Weight Gain Guidelines (by Pre-Pregnancy BMI)
| Pre-Pregnancy BMI | Category | Total Gain | Weekly Gain (2nd & 3rd Trimester) |
|---|---|---|---|
| Below 18.5 | Underweight | 13-18 kg | 0.5-0.6 kg/week |
| 18.5 - 24.9 | Normal | 11-16 kg | 0.4-0.5 kg/week |
| 25.0 - 29.9 | Overweight | 7-11 kg | 0.2-0.3 kg/week |
| 30.0+ | Obese | 5-9 kg | 0.2-0.3 kg/week |
- Normal BMI: 17-25 kg total
- Overweight: 14-23 kg total
- Obese: 11-19 kg total
Target Heart Rate Zones
| Age | Max HR | Fat Burn (60-70%) | Cardio (70-85%) | Peak (85-95%) |
|---|---|---|---|---|
| 20 | 200 | 120-140 | 140-170 | 170-190 |
| 25 | 195 | 117-136 | 136-166 | 166-185 |
| 30 | 190 | 114-133 | 133-162 | 162-181 |
| 35 | 185 | 111-130 | 130-157 | 157-176 |
| 40 | 180 | 108-126 | 126-153 | 153-171 |
| 45 | 175 | 105-123 | 123-149 | 149-166 |
| 50 | 170 | 102-119 | 119-145 | 145-162 |
| 55 | 165 | 99-116 | 116-140 | 140-157 |
| 60 | 160 | 96-112 | 112-136 | 136-152 |
📊 Health & Fitness Calculators by Category
🤰 Pregnancy & Fertility Calculators
Track pregnancy, ovulation, and fertility planning
💪 Body Composition & Weight Calculators
Measure body metrics and composition
🔥 Calorie & Nutrition Calculators
Plan diet for weight loss, maintenance, or muscle gain
🏋️ Fitness & Training Calculators
Optimize workouts and athletic performance
💧 Hydration & Wellness Calculators
Track health metrics and wellness
Browse Health & Fitness Calculators
BMI Calculator: Body Mass Index, Category & Healthy Range
Calculate BMI from height and weight, see adult BMI category, healthy weight range, health risk context, metric/imperial inputs, and BMI limitations.
Period Calculator
Period calculator with calendar view and reminders! Track next period, ovulation, and fertile window. Add to Outlook, Gmail, Apple Calendar with one click. Visual calendar marks all important dates automatically.
Ovulation Calculator
Calculate ovulation day, fertile window, and best days to conceive. Track menstrual cycle and predict fertility period for pregnancy planning with personalized calendar.
Calorie Calculator: Daily Calories, BMR, TDEE & Macros
Calculate daily calorie needs for weight loss, maintenance, or muscle gain using BMR, TDEE, activity level, Mifflin-St Jeor, and macro guidance. Educational nutrition estimate.
Lean Body Mass Calculator
Advanced lean body mass calculator using Boer, James & Hume formulas. Calculate LBM, FFM, fat mass, muscle mass percentage with gender-specific accuracy. Includes body composition breakdown, FFMI calculator, athlete comparisons, real case studies, progress tracking, and nutrition recommendations for bodybuilding & fitness.
Pregnancy Due Date Calculator
Estimate pregnancy due date, current week, trimester, and conception window from last menstrual period (LMP), conception date, or IVF transfer. Includes week-by-week context and due date accuracy guidance.
BMR Calculator: Basal Metabolic Rate & Resting Calories
Calculate basal metabolic rate, resting calorie burn, and activity-adjusted calorie needs using Mifflin-St Jeor or Harris-Benedict with age, sex, weight, and height.
Body Fat Calculator
Calculate body fat percentage using US Navy method, skinfold measurements, or BMI formula. Assess fat mass, lean mass, and body composition for fitness and health tracking.
Calorie Burned Calculator
Calculate calories burned during exercise with scientifically-validated MET values. Track running, walking, cycling, swimming calories plus 12 activities. Get weekly/monthly projections, food equivalents, and personalized weight loss estimates. Free calorie burn calculator with lbs/kg conversion.
Ideal Weight Calculator
Estimate your ideal body weight and healthy target weight range by height, age, gender, and frame size for realistic weight goals.
TDEE Calculator: Maintenance Calories & Activity Level
Calculate TDEE, maintenance calories, BMR plus activity multiplier, and calorie targets for weight loss, maintenance, or muscle gain. Educational estimate only.
Conception Calculator
Calculate conception date from due date, birth date, or LMP. Estimate when baby was conceived and determine conception window for pregnancy planning.
BAC Calculator
Calculate Blood Alcohol Content (BAC) level based on drinks consumed, weight, gender, and time. Estimate intoxication level and time to sober up for responsible drinking.
Macro Calculator
Calculate macronutrient ratio (protein, carbs, fats) for diet goals. Get personalized macro split for weight loss, muscle gain, or maintenance with calorie and gram breakdown.
Water Intake Calculator
Calculate daily water intake recommendations based on weight, activity level, climate, and health status. Stay hydrated with personalized fluid requirements in liters or ounces.
One Rep Max Calculator
Calculate one rep max (1RM) for weightlifting exercises. Estimate maximum strength, training percentages, and progressive overload using Brzycki, Epley, or Lombardi formulas.
Protein Calculator
Calculate daily protein requirements for muscle building, weight loss, or maintenance. Get personalized protein intake in grams based on body weight, activity level, and fitness goals.
Target Heart Rate Calculator
Calculate target heart rate zones for cardio exercise based on age and resting heart rate. Optimize fat burn, aerobic, and anaerobic training zones with Karvonen formula.
Pregnancy Weight Gain Calculator
Calculate healthy pregnancy weight gain by trimester based on pre-pregnancy BMI. Track recommended weight gain range for single and multiple pregnancies.
Healthy Body Weight Calculator
Calculate healthy weight range for your height, age, and gender. Determine ideal weight using WHO BMI standards and multiple scientific formulas for optimal health.
Carbohydrate Calculator
Estimate daily carbs in grams from weight, activity, goal, and diet type (balanced to keto). Uses an in-tool energy estimate—not a substitute for medical nutrition advice.
Body Surface Area Calculator
Calculate body surface area (BSA) for medical dosing using Mosteller, DuBois, or Haycock formula. Essential for chemotherapy, drug dosing, and medical calculations.
Workout Timer
Free online workout timer for HIIT, Tabata, circuit training, and boxing. Set custom intervals, rounds, and rest periods. Audio alerts, fullscreen mode, and preset workouts. No download required.
Fat Intake Calculator
Calculate daily healthy fat intake for optimal nutrition. Determine fat requirements in grams and calories based on diet type, activity level, and health goals.
IVF Cost Calculator
Calculate IVF treatment costs including medications, procedures, and facility fees. See insurance coverage options and financing help. Compare costs by state. Estimate your out-of-pocket expenses for IVF treatment with detailed breakdown.
🔥 Top Health Calculators for Everyday Wellness
Find the right health tool for your goal: weight loss, calorie planning, body fat estimate, pregnancy timing, hydration tracking, and strength training targets. Each calculator is built to give clear results, practical recommendations, and quick next steps.
Most popular
BMI Calculator
Weight status, healthy range, and body mass index
Nutrition planning
Calorie Calculator
Daily calorie targets for weight loss, maintenance, or muscle gain
Body composition
Body Fat Calculator
Estimate body fat percentage using proven methods
Pregnancy planning
Pregnancy Due Date Calculator
Predict due date, trimester, and week-by-week progress