65 free calculators — BMI, BMR, TDEE, calories, macros, body fat and hydration — general reference tools, not medical advice.
Calculate Body Mass Index from height and weight, with WHO category context.
Use calculatorEstimate basal metabolic rate — calories burned at complete rest.
Use calculatorTotal daily energy expenditure: your full-day calorie burn including activity.
Use calculatorSee daily calorie targets for losing, maintaining or gaining weight.
Use calculatorSplit your daily calories into protein, carbs and fat gram targets.
Use calculatorEstimate body fat percentage using the U.S. Navy circumference method.
Use calculatorSee ideal weight ranges from four classic formulas plus the healthy-BMI span.
Use calculatorEstimate daily hydration needs from body weight and activity level.
Use calculatorCalculate daily protein needs from weight, activity level and goal — see grams per day, per meal and per kg.
Use calculatorEstimate due date from last menstrual period (LMP) using Naegele's rule — 280 days or 40 weeks from LMP.
Use calculatorEstimate ovulation date and fertile window from LMP and cycle length — see next 3 cycles predicted.
Use calculatorEstimate sleep debt from hours slept vs needed — see weekly deficit, recovery time and nightly catch-up needed.
Use calculatorCalculate recommended daily fiber intake by age and sex, plus food equivalents — see grams per day and per 1000 kcal.
Use calculatorEstimate lean body mass from weight, height and sex using Boer formula — see LBM, body fat mass and ideal weight range.
Use calculatorCheck sodium intake from foods and salt — see daily total, % of limit, and low-sodium swaps.
Use calculatorEstimate daily water needs from weight, activity and climate — see liters, cups and hourly intake.
Use calculatorEstimate vitamin D from sun, food and supplements — see total IU, % of RDA and safe upper limit.
Use calculatorCheck iron intake vs RDA by age and sex — see mg/day, % of RDA and heme vs non-heme tips.
Use calculatorCalculate calorie deficit needed to lose weight: enter current weight, goal weight, weeks and TDEE to see daily deficit and intake.
Use calculatorCalculate keto macros from calories, weight and activity — see carbs, protein, fat grams and net carbs for ketosis.
Use calculatorCalculate waist-to-hip ratio (WHR) from waist and hip measurements — see ratio, health risk category and ideal range.
Use calculatorCalculate waist-to-height ratio (WHtR) — see ratio, health category and keep waist less than half height rule.
Use calculatorEstimate body water percentage from weight, height, age and sex using Watson formula — see total body water liters and percent.
Use calculatorCalculate BMI Prime from BMI and upper limit — see BMI Prime, ideal weight range and health category.
Use calculatorCalculate ideal weight range from height and sex using Robinson, Miller and Hamwi formulas — see healthy range and BMI.
Use calculatorCalculate protein per meal from daily protein and meals — see per meal grams, per kg and distribution.
Use calculatorEstimate sleep quality from hours, interruptions and feeling — see quality score, efficiency and recommendations.
Use calculatorCalculate daily caffeine intake from coffee, tea, energy drinks and soda — see total mg, % of 400mg limit and sleep impact.
Use calculatorCalculate daily sugar intake from foods and drinks — see total grams, teaspoons, % of 50g limit and calories from sugar.
Use calculatorEstimate daily cholesterol intake from foods — see total mg, % of 300mg limit and food breakdown.
Use calculatorConvert blood sugar between mg/dL and mmol/L, estimate HbA1c from average glucose and category.
Use calculatorCalculate sunscreen needed from body area, SPF and time outdoors — see amount, reapplication and protection.
Use calculatorCalculate meditation time needed from stress level and goal — see daily minutes, weekly total and schedule.
Use calculatorCalculate breathing exercise from technique and duration — see breaths, cycles and time per phase.
Use calculatorCalculate hand washing effectiveness from duration and technique — see germ reduction and recommended time.
Use calculatorEstimate electrolyte needs from weight, activity and sweat — see sodium, potassium, magnesium needs and hydration.
Use calculatorCheck magnesium intake vs RDA by age and sex — see mg/day, % of RDA and food sources.
Use calculatorCheck potassium intake vs AI by age and sex — see mg/day, % of AI and food sources.
Use calculatorCheck calcium intake vs RDA by age and sex — see mg/day, % of RDA and food sources.
Use calculatorCheck zinc intake vs RDA by age and sex — see mg/day, % of RDA and food sources.
Use calculatorCheck vitamin C intake vs RDA by age and sex — see mg/day, % of RDA and food sources.
Use calculatorCheck vitamin A intake vs RDA by age and sex — see mcg RAE/day, % of RDA and food sources.
Use calculatorCheck vitamin B12 intake vs RDA — see mcg/day, % of RDA and food sources.
Use calculatorCheck folate intake vs RDA — see mcg DFE/day, % of RDA and food sources.
Use calculatorCheck omega-3 intake vs AI — see grams/day, % of AI and food sources for EPA/DHA and ALA.
Use calculatorCheck vitamin E intake vs RDA — see mg/day, % of RDA and food sources.
Use calculatorCheck vitamin K intake vs AI — see mcg/day, % of AI and food sources.
Use calculatorCheck biotin intake vs AI — see mcg/day, % of AI and food sources.
Use calculatorCheck niacin (B3) intake vs RDA — see mg NE/day, % of RDA and food sources.
Use calculatorCheck riboflavin (B2) intake vs RDA — see mg/day, % of RDA and food sources.
Use calculatorCheck thiamine (B1) intake vs RDA — see mg/day, % of RDA and food sources.
Use calculatorCheck vitamin B6 intake vs RDA — see mg/day, % of RDA and food sources.
Use calculatorCheck pantothenic acid (B5) intake vs AI — see mg/day, % of AI and food sources.
Use calculatorCheck choline intake vs AI — see mg/day, % of AI and food sources.
Use calculatorCheck manganese intake vs AI — see mg/day, % of AI and food sources.
Use calculatorCheck copper intake vs RDA — see mcg/day, % of RDA and food sources.
Use calculatorCheck selenium intake vs RDA — see mcg/day, % of RDA and food sources.
Use calculatorCheck chromium intake vs AI — see mcg/day, % of AI and food sources.
Use calculatorCheck molybdenum intake vs RDA — see mcg/day, % of RDA and food sources.
Use calculatorCheck iodine intake vs RDA — see mcg/day, % of RDA and food sources.
Use calculatorCheck phosphorus intake vs RDA — see mg/day, % of RDA and food sources.
Use calculatorCheck fluoride intake vs AI — see mg/day, % of AI and sources.
Use calculatorCheck chloride intake vs AI — see mg/day, % of AI and sources.
Use calculatorCheck sulfur intake from protein — see grams/day and % of estimated needs.
Use calculatorCheck nickel intake vs AI — see mcg/day, % of AI and sources.
Use calculatorHealth calculators: BMI, BMR, TDEE, calories, macros, body fat and hydration — general reference tools, not medical advice. Browse 65 free tools for health tasks. Enter values for instant results with formulas shown. No signup needed.
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| Calculator | What It Does | Formula |
|---|---|---|
| BMI Calculator | Calculate Body Mass Index from height and weight, with WHO category context. | BMI = weight (kg) ÷ height² (m) |
| BMR Calculator | Estimate basal metabolic rate — calories burned at complete rest. | Mifflin-St Jeor: BMR = 10·kg + 6.25·cm − 5·age + (male: +5 | female: −161) |
| TDEE Calculator | Total daily energy expenditure: your full-day calorie burn including activity. | TDEE = BMR × activity multiplier (1.2 sedentary → 1.9 extremely active) |
| Calorie Calculator | See daily calorie targets for losing, maintaining or gaining weight. | target = TDEE ± (weekly goal kg × 7,700 ÷ 7); BMR via Mifflin-St Jeor |
| Macro Calculator | Split your daily calories into protein, carbs and fat gram targets. | grams = (calories × share) ÷ kcal-per-gram (4 for protein/carbs, 9 for fat) |
| Body Fat Calculator | Estimate body fat percentage using the U.S. Navy circumference method. | Navy method uses log₁₀ of circumference ratios: men: 86.01·log₁₀(waist−neck) − 70.041·log₁₀(height) + 36.76 |
| Ideal Weight Calculator | See ideal weight ranges from four classic formulas plus the healthy-BMI span. | Devine: 50 kg (male) or 45.5 kg (female) + 2.3 kg per inch over 5 feet |
| Water Intake Calculator | Estimate daily hydration needs from body weight and activity level. | baseline ≈ 33 ml per kg body weight; add ~350 ml per 30 min exercise; more in heat |
| Protein Intake Calculator | Calculate daily protein needs from weight, activity level and goal — see grams per day, per meal and per kg. | Protein = weight(kg) × factor: sedentary 0.8, active 1.2-1.6, athlete 1.6-2.2 g/kg; goal adjusts within range |
| Pregnancy Due Date Calculator | Estimate due date from last menstrual period (LMP) using Naegele's rule — 280 days or 40 weeks from LMP. | Due date = LMP + 280 days (40 weeks) = LMP + 1 year - 3 months + 7 days |
| Ovulation Calculator | Estimate ovulation date and fertile window from LMP and cycle length — see next 3 cycles predicted. | Ovulation = LMP + cycleLength - 14 days; Fertile window = ovulation ± 3 days (approx) |
| Sleep Debt Calculator | Estimate sleep debt from hours slept vs needed — see weekly deficit, recovery time and nightly catch-up needed. | Debt = (needed - actual) * days; Recovery nights = debt / (recoveryHoursPerNight) where recovery is limited |
| Fiber Intake Calculator | Calculate recommended daily fiber intake by age and sex, plus food equivalents — see grams per day and per 1000 kcal. | AI 14g / 1000 kcal; or age/sex AI: M 34g (19-50), 28g (51+); F 28g (19-50), 22g (51+); plus 14g per 1000 kcal check |
| Lean Body Mass Calculator | Estimate lean body mass from weight, height and sex using Boer formula — see LBM, body fat mass and ideal weight range. | Boer: Male LBM = 0.407*weight + 0.267*height -19.2; Female = 0.252*weight + 0.473*height -48.3 |
| Sodium Intake Calculator | Check sodium intake from foods and salt — see daily total, % of limit, and low-sodium swaps. | Total = meals + salt*2300mg (1 tsp salt ≈ 2300mg sodium); % = total/2300*100 |
| Hydration Calculator | Estimate daily water needs from weight, activity and climate — see liters, cups and hourly intake. | Base = weight*0.033 L; then +0.35L per 30min exercise, +0.3L for hot/humid |
| Vitamin D Calculator | Estimate vitamin D from sun, food and supplements — see total IU, % of RDA and safe upper limit. | Total = sun*~8 IU per minute (midday, fair skin, arms/legs) + food + supplement; RDA 600 IU (19-70), 800 (71+) |
| Iron Intake Calculator | Check iron intake vs RDA by age and sex — see mg/day, % of RDA and heme vs non-heme tips. | RDA: M 8mg (19+), F 18mg (19-50), 8mg (51+), 27mg pregnancy; % = intake/RDA*100 |
| Calorie Deficit Calculator | Calculate calorie deficit needed to lose weight: enter current weight, goal weight, weeks and TDEE to see daily deficit and intake. | Total deficit = (current-goal)*7700 kcal; Daily deficit = total/weeks/7; Target = TDEE - daily deficit |
| Keto Macro Calculator | Calculate keto macros from calories, weight and activity — see carbs, protein, fat grams and net carbs for ketosis. | Carbs 5% cals, Protein 1.6-2.2g/kg, Fat = remaining cals/9 |
| Waist to Hip Ratio Calculator | Calculate waist-to-hip ratio (WHR) from waist and hip measurements — see ratio, health risk category and ideal range. | WHR = waist / hip; Risk: M >0.90, F >0.85 high |
| Waist to Height Ratio Calculator | Calculate waist-to-height ratio (WHtR) — see ratio, health category and keep waist less than half height rule. | WHtR = waist / height; Healthy <0.5, 0.5-0.6 increased, >0.6 high |
| Body Water Percentage Calculator | Estimate body water percentage from weight, height, age and sex using Watson formula — see total body water liters and percent. | Watson: Male TBW =2.447 -0.09516*age +0.1074*height +0.3362*weight; Female = -2.097 +0.1069*height +0.2466*weight |
| BMI Prime Calculator | Calculate BMI Prime from BMI and upper limit — see BMI Prime, ideal weight range and health category. | BMI Prime = BMI / 25 |
| Ideal Weight Range Calculator | Calculate ideal weight range from height and sex using Robinson, Miller and Hamwi formulas — see healthy range and BMI. | Robinson: M 52+1.9*(in-60), F 49+1.7*(in-60); Hamwi: M 48+2.7*(in-60), F 45.5+2.2*(in-60) |
| Protein Per Meal Calculator | Calculate protein per meal from daily protein and meals — see per meal grams, per kg and distribution. | Per meal = daily / meals; Per kg per meal = perMeal/weight |
| Sleep Quality Calculator | Estimate sleep quality from hours, interruptions and feeling — see quality score, efficiency and recommendations. | Efficiency = asleep/timeInBed*100; Score = efficiency*0.6 + (10-awakenings*2)*4 + feeling*2 weighted |
| Caffeine Intake Calculator | Calculate daily caffeine intake from coffee, tea, energy drinks and soda — see total mg, % of 400mg limit and sleep impact. | Total = coffee*95 + tea*47 + energy*80 + soda*40 mg; % = total/400*100 |
| Sugar Intake Calculator | Calculate daily sugar intake from foods and drinks — see total grams, teaspoons, % of 50g limit and calories from sugar. | Total = soda*39g + sweets*25g + other; Teaspoons = total/4; % = total/50*100; Calories = total*4 |
| Cholesterol Intake Calculator | Estimate daily cholesterol intake from foods — see total mg, % of 300mg limit and food breakdown. | Total = eggs*186 + meat*75 + dairy*30 + other; % = total/300*100 |
| Blood Sugar Calculator | Convert blood sugar between mg/dL and mmol/L, estimate HbA1c from average glucose and category. | mmol = mg/dL /18.01559; HbA1c% = (avg +46.7)/28.7 (ADAG) |
| Sunscreen Calculator | Calculate sunscreen needed from body area, SPF and time outdoors — see amount, reapplication and protection. | Amount: face 5ml, face+arms 15ml, full 35ml; Reapply every 2 hours; SPF 50 blocks 98% |
| Meditation Time Calculator | Calculate meditation time needed from stress level and goal — see daily minutes, weekly total and schedule. | Beginner: stress*2 min, intermediate: stress*1.5, advanced: stress*1.2; plus 5 min base |
| Breathing Exercise Calculator | Calculate breathing exercise from technique and duration — see breaths, cycles and time per phase. | Box: 16s per breath (4+4+4+4), 4-7-8: 19s, Coherent: 10s; Breaths = minutes*60 / breathTime |
| Hand Washing Calculator | Calculate hand washing effectiveness from duration and technique — see germ reduction and recommended time. | Reduction: proper 20s ~90%, 10s ~50%, quick rinse ~20%; Recommended 20s |
| Electrolyte Calculator | Estimate electrolyte needs from weight, activity and sweat — see sodium, potassium, magnesium needs and hydration. | Sodium 500mg per hour moderate, 300 low, 800 high; Potassium 200mg per hour; Magnesium 50mg per hour |
| Magnesium Intake Calculator | Check magnesium intake vs RDA by age and sex — see mg/day, % of RDA and food sources. | RDA: M 400-420, F 310-320; % = intake/RDA*100 |
| Potassium Intake Calculator | Check potassium intake vs AI by age and sex — see mg/day, % of AI and food sources. | AI: M 3400, F 2600 (19+); % = intake/AI*100 |
| Calcium Intake Calculator | Check calcium intake vs RDA by age and sex — see mg/day, % of RDA and food sources. | RDA: 1000mg 19-50, 1200mg 51+ women/70+ men; % = intake/RDA*100 |
| Zinc Intake Calculator | Check zinc intake vs RDA by age and sex — see mg/day, % of RDA and food sources. | RDA: M 11mg, F 8mg (19+); % = intake/RDA*100 |
| Vitamin C Intake Calculator | Check vitamin C intake vs RDA by age and sex — see mg/day, % of RDA and food sources. | RDA: M 90mg, F 75mg (19+); Smokers +35mg; % = intake/RDA*100 |
| Vitamin A Intake Calculator | Check vitamin A intake vs RDA by age and sex — see mcg RAE/day, % of RDA and food sources. | RDA: M 900, F 700 mcg RAE (19+); % = intake/RDA*100 |
| Vitamin B12 Intake Calculator | Check vitamin B12 intake vs RDA — see mcg/day, % of RDA and food sources. | RDA: 2.4 mcg 19+ (2.6 pregnancy, 2.8 lactation); % = intake/2.4*100 |
| Folate Intake Calculator | Check folate intake vs RDA — see mcg DFE/day, % of RDA and food sources. | RDA: 400 mcg DFE 19+ (600 pregnancy, 500 lactation); % = intake/RDA*100; DFE = food folate + 1.7*folic acid |
| Omega-3 Intake Calculator | Check omega-3 intake vs AI — see grams/day, % of AI and food sources for EPA/DHA and ALA. | AI: M 1.6g, F 1.1g ALA 19+; % = intake/AI*100; EPA/DHA aim 250mg |
| Vitamin E Intake Calculator | Check vitamin E intake vs RDA — see mg/day, % of RDA and food sources. | RDA: 15mg 19+; % = intake/15*100 |
| Vitamin K Intake Calculator | Check vitamin K intake vs AI — see mcg/day, % of AI and food sources. | AI: M 120, F 90 mcg; % = intake/AI*100 |
| Biotin Intake Calculator | Check biotin intake vs AI — see mcg/day, % of AI and food sources. | AI: 30 mcg 19+; % = intake/30*100 |
| Niacin Intake Calculator | Check niacin (B3) intake vs RDA — see mg NE/day, % of RDA and food sources. | RDA: M 16, F 14 mg NE; % = intake/RDA*100 |
| Riboflavin Intake Calculator | Check riboflavin (B2) intake vs RDA — see mg/day, % of RDA and food sources. | RDA: M 1.3, F 1.1 mg; % = intake/RDA*100 |
| Thiamine Intake Calculator | Check thiamine (B1) intake vs RDA — see mg/day, % of RDA and food sources. | RDA: M 1.2, F 1.1 mg; % = intake/RDA*100 |
| Pyridoxine Intake Calculator | Check vitamin B6 intake vs RDA — see mg/day, % of RDA and food sources. | RDA: 1.3mg 19-50, 1.7M 51+, 1.5F 51+; % = intake/RDA*100 |
| Pantothenic Acid Intake Calculator | Check pantothenic acid (B5) intake vs AI — see mg/day, % of AI and food sources. | AI: 5mg 19+; % = intake/5*100 |
| Choline Intake Calculator | Check choline intake vs AI — see mg/day, % of AI and food sources. | AI: M 550, F 425 mg; % = intake/AI*100 |
| Manganese Intake Calculator | Check manganese intake vs AI — see mg/day, % of AI and food sources. | AI: M 2.3, F 1.8 mg; % = intake/AI*100 |
| Copper Intake Calculator | Check copper intake vs RDA — see mcg/day, % of RDA and food sources. | RDA: 900 mcg 19+; % = intake/900*100 |
| Selenium Intake Calculator | Check selenium intake vs RDA — see mcg/day, % of RDA and food sources. | RDA: 55 mcg 19+; % = intake/55*100 |
| Chromium Intake Calculator | Check chromium intake vs AI — see mcg/day, % of AI and food sources. | AI: M 35, F 25 mcg; % = intake/AI*100 |
| Molybdenum Intake Calculator | Check molybdenum intake vs RDA — see mcg/day, % of RDA and food sources. | RDA: 45 mcg 19+; % = intake/45*100 |
| Iodine Intake Calculator | Check iodine intake vs RDA — see mcg/day, % of RDA and food sources. | RDA: 150 mcg 19+ (220 pregnancy, 290 lactation); % = intake/RDA*100 |
| Phosphorus Intake Calculator | Check phosphorus intake vs RDA — see mg/day, % of RDA and food sources. | RDA: 700mg 19+; % = intake/700*100 |
| Fluoride Intake Calculator | Check fluoride intake vs AI — see mg/day, % of AI and sources. | AI: M 4, F 3 mg; % = intake/AI*100 |
| Chloride Intake Calculator | Check chloride intake vs AI — see mg/day, % of AI and sources. | AI: 2300mg 19-50, 2000 51-70, 1800 71+; % = intake/AI*100 |
| Sulfur Intake Calculator | Check sulfur intake from protein — see grams/day and % of estimated needs. | Sulfur ~ protein*0.02g (2% of protein is sulfur amino acids) |
| Nickel Intake Calculator | Check nickel intake vs AI — see mcg/day, % of AI and sources. | No RDA, typical intake 100-300 mcg; AI not set, use typical |
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