Health & Body
234 free online calculators — instant results, no sign-up
All 234 Health & Body Tools
HOT
BMI Calculator
Body mass index with healthy range by standardBody Fat Calculator
Circumference-based estimate with ACE classificationWaist-to-Hip Ratio Calculator
WHR with abdominal obesity risk referenceBMR Calculator
Basal metabolic rate — Mifflin & Harris-Benedict equationsTDEE Calculator
Total daily energy expenditure by activity levelIdeal Weight Calculator
Devine, Robinson and Miller formulasPregnancy Due Date Calculator
Due date, gestational week and trimestersMaternity Allowance Calculator
Wage ÷ 30 × leave days and employer top-upQTc Correction Calculator
Bazett, Fridericia, Framingham, Hodges with sex-specific bandsSodium to Salt Converter
1 g salt = 400 mg sodium, NRV% and GB 28050 bandsGlycemic Load Calculator
GL = GI x available carbs / 100 with low/mid/high bandsWater Intake Calculator
Recommended daily water by weight and activityHeart Rate Zone Calculator
Max heart rate and training intensity zonesHeadphone Safety Calculator
NIOSH 3-dB rule, 60-60 principle, daily quotaNEWBody Surface Area Calculator
Five BSA formulas with 1.73m² referenceNEWPregnancy Weight Gain Calculator
Recommended gain vs actual — IOM guidelinesNEWSleep Calculator
Sleep duration, bedtime and wake-up planningNEWDaily Calorie Calculator
Calorie needs from BMR and activity factorNEWRunning Pace Calculator
Pace per km/mile, speed and finish timeRunning Shoes Mileage Calculator
Shoe life by type, weight & rotation → pairs per yearOvulation Calculator
Ovulation day and fertile window from cycle lengthRace Finish Time Predictor
5K/10K/half/full marathon — Riegel formulaNaismith Hiking Time Calculator
Distance + ascent rule of thumbOne Rep Max Calculator
Epley & Brzycki formulas with training weight tableBarbell Plate Calculator
Target weight to per-side plate loading planContact Lens Power Converter
Spectacle to contact power via vertex distance, 0.25D stepsVision Record Converter
5-point record, decimal, logMAR and SnellenAQI Calculator
Six-pollutant IAQI interpolation per HJ 633-2012 with level bandsBAC Calculator
Blood alcohol estimate, legal limits and sobering timeMacro Calculator
Protein, carbs and fat grams by goal-based ratioChild Height Predictor
Target adult height from parents with expected rangeBlood Pressure Calculator
BP category, pulse pressure and reference tablesCaffeine Intake Calculator
Total caffeine from drinks vs the 400mg daily limitSmoking Cost Calculator
Money burned, opportunity cost and health ledgerPack-Year Calculator
Smoking index, lung cancer screening gradeProtein Intake Calculator
Daily protein needs by weight and goal, food equivalentsSteps to Calories Calculator
Steps to distance, calories burned and walking timeVO2 Max Calculator
Cooper 12-min run and resting-HR aerobic fitness estimateFFMI Calculator
Fat-free mass index with natural muscle limit ratingLean Body Mass Calculator
Boer & James formulas for lean mass and fat massWaist-to-Height Ratio Calculator
Waist ÷ height — central obesity gradingPeriod & Ovulation Calculator
Cycle prediction, ovulation day and fertile windowBlood Type Inheritance Calculator
Parent blood types → child blood type oddsPunnett Square Calculator
Gene cross → genotype & phenotype ratiosDihybrid Cross Calculator
16-box square, 9:3:3:1 independent assortmentIV Drip Rate Calculator
Drops/min, pump mL/h, drop factor, infusion timeUric Acid Calculator
μmol/L ↔ mg/dL conversion and hyperuricemia gradingKids Fever Medicine Dosage
Weight-based ibuprofen and acetaminophen dosingBaby Milk Intake Calculator
Daily milk volume and feeding frequency by agePregnancy Week Calculator
Gestational age, due date and trimester milestonesFetal Weight Calculator
BPD/HC/AC/FL → Hadlock weight estimateeGFR Calculator
CKD-EPI 2021 equation, CKD stagingExercise Calorie Calculator
MET-based burn for 40+ activitiesWeight Loss Time Calculator
7700 kcal rule, deficit projectionBaby Vaccine Schedule
China national immunization dates plannerCreatinine Clearance Calculator
Cockcroft-Gault, kidney stagingIntermittent Fasting Calculator
16:8/18:6/20:4 eating windowsRace Time Predictor
Riegel formula, all distancesBody Water Calculator
Watson formula, water percentageBlood Glucose Converter
mmol/L ↔ mg/dL, HbA1c → eAG, verdictsSafe Period Calculator
Calendar method, fertile window, 3-cycle tableChild Growth Standards
WHO 0-5y weight/height percentilesCholesterol Calculator
Friedewald LDL + lipid gradingBody Age Calculator
8 lifestyle factors · biological ageFTP Calculator (Cycling)
20min x0.95 · W/kg level · power zonesBaby Cereal Portion Calculator
age stage · grams per meal · bag lasts · milk refOrthodontics Cost Calculator
appliance tier · extractions · visits · retainersDental Implant Cost Calculator
pooled implant · crown · service fee · bone graftAnnual Checkup Budget Calculator
plan tier · gastroscopy · CT · tumor markersWisdom Tooth Extraction Cost Calculator
impaction tier · teeth · imaging · medsPurine Intake Calculator
food purine table × amount · daily capAnion Gap Calculator
AG=Na⁺−(Cl⁻+HCO₃⁻) · metabolic acidosis typingMaintenance Fluid Calculator
4-2-1 rule · hourly/daily maintenance · pediatricsCarb Counting Insulin Calculator
Meal insulin from carb ratio plus correction doseCorrected Sodium Calculator
Sodium correction for hyperglycemiaBlood Volume Calculator
Estimated blood volume by weight and sexGlasgow Coma Scale
GCS eye, verbal and motor scoringAPGAR Score
Newborn APGAR at 1 and 5 minutesCURB-65 Score
Community-acquired pneumonia severityCHA2DS2-VASc Score
Atrial fibrillation stroke riskWells Score for DVT
Pretest probability of deep vein thrombosisqSOFA Score
Quick sepsis-related organ failure assessmentChild-Pugh Score
Liver disease severity gradingBody Fat (US Navy Method)
Navy circumference body fat estimateDaily Water Intake
Daily hydration target from weight and activityPM2.5 Cigarette Equivalent
Daily PM2.5 as cigarettes per dayLipid Unit Converter
Cholesterol and triglyceride mmol to mg/dLVitamin D Converter
IU to mcg and daily needsElectrolyte Drink Mixer
Homemade ORS and sports drink ratiosFiber Intake Calculator
Get your daily fiber target from calorie intake with food examples.Added Sugar Limit Calculator
Compute your WHO added-sugar ceiling and convert sugary drinks to grams.HbA1c Converter
Convert HbA1c between % and mmol/mol with estimated average glucose.Calorie Deficit & Weight Loss
Daily calorie deficit, expected weight loss in kilograms and timeline from TDEE versus intake.Daily Calcium Intake
Recommended daily calcium by age and pregnancy or lactation status, converted into milk and tofu servings.Biorhythm Curves
Physical, emotional and intellectual biorhythm positions from your birth date, with peaks and lows.Topical FTU Dosing
Topical cream dosing in fingertip units (FTU) by body area, with tube count for the full course.Blood Donation Interval
Next eligible donation date from your last whole-blood donation, with recovery timeline.Nap Length Planner
Wake-up times for a 20-minute power nap versus a full 90-minute cycle, with the coffee nap trick.Alcohol Intake Calculator
Pure alcohol grams by drink type and count, versus daily limits.Screen Time Calculator
Convert daily screen hours into yearly days, sleep loss and real-life equivalents.Jump Rope Calorie Calculator
Calories burned jumping rope by weight, duration and pace.20-20-20 Eye Rule
Screen-time based 20-20-20 break counts and daily eye-load summary.Sedentary Break Reminder
Break counts and suggested movement for long sitting sessions.Swimming Calories
Swimming calorie burn by stroke, duration and body weight.Rowing Machine Pace & Power
Watts and calorie burn from your 500m split on the erg.Golf Handicap Differential
Handicap differential from score, course rating and slope.Eye Exam Interval
Recommended refraction check interval by age group and myopia degree.Elliptical Calories
Calories burned on the elliptical from body weight and session length.Climbing Calories
Calories burned indoor climbing from body weight and session length.Toothbrush Replacement
Replacement date from brush type; swap before bristles splay.Dental Floss Usage
Days per roll and annual rolls from daily floss length and roll size.Step Goal Burn
Distance and calories from daily steps and stride length.Iron Intake Gap
Iron gap between the recommended intake and today’s actual intake.Boxing Calories
Calories burned by boxing style, duration and body weight.Yoga Calories
Calories burned by yoga style, duration and body weight.Stretching Time Plan
Dynamic and static stretching minutes from training duration.Mask Usage
Monthly mask count from daily wear scenarios and headcount.Hand Sanitizer Usage
Monthly hand sanitizer use from dose size, daily uses and headcount.Nail Trim Schedule
Next nail trim date from growth rate and trim length target.Mouthwash Usage
Monthly mouthwash consumption from dose size and daily uses.Contact Lens Solution
How long a bottle of contact lens solution lasts from daily usage.Sleep Debt
Weekly sleep debt from target vs actual sleep and repayment plan.Step Length & Distance
Step length from height and distance covered by your step count.Standing Desk Switches
Sit-stand switch count and standing target from work hours.Dog Walk Calories
Calories burned walking your dog for both you and the dog.Hand Washing Time
Daily hand-washing time and water use from daily occasions.Sunscreen Reapply Timer
Sunscreen reapplication interval by SPF and activity.Cycling Calories
Calories burned cycling by speed tier and body weight.Hiking Water Needs
Water to carry for a hike by duration and temperature.Sleep Cycle Bedtime
Bedtime from wake time in 90-minute sleep cycles.Caffeine Cut-off Time
Last coffee time from bedtime and metabolism speed.HIIT Calories
HIIT calorie burn with EPOC afterburn effect.Rest Between Sets
Rest seconds between sets by training goal.Ice Pack Schedule
Ice sessions in the golden 48h window by interval.Macro Split
Protein, carb and fat grams from calories and split.Warm-up Duration
Warm-up minutes by activity, intensity and temperature.Hiking Pack Weight
Safe pack weight from bodyweight and trip type.Muscle Recovery Days
Recovery hours and next-session date by muscle group and intensity.Haircut Cycle
Next haircut date by style and growth rate.Dinner Cutoff Time
Latest dinner time from bedtime and digestion gap.Protein Per Meal
Grams per meal from daily protein target.Squat Knee Load
Patellofemoral reference load from bodyweight and bar weight.Screen Curfew Time
Phone-down cutoff from bedtime and curfew length.Sun Exposure Time
Minutes for vitamin D synthesis by time slot and skin type.Sauna Session Time
Sauna session minutes by level and temperature.Foam Roller Time
Foam rolling minutes by body part.Pillow Height
Compressed pillow height by sleep position.Insect Repellent Duration
Repellent reapply interval by DEET level and activity.Badminton String Tension
Racket string tension by play style and weight.Kinesiology Tape Length
Tape strip length by knee circumference.Swim Goggle Lifespan
Goggle anti-fog lifespan by weekly swims.Ear Plug Noise Level
Effective dB after ear plugs by NRR.Sun Shirt UPF Left
Remaining UPF protection by wash count.Yoga Mat Thickness
Mat thickness by weight and practice style.Jump Rope Length Calculator
Rope length from height - stand on midpoint, handles reach chest.Yoga Ball Size Calculator
Match 55/65/75 cm ball by height - thighs parallel when seated.Resistance Band Calculator
Match 15/25/35 lb band by bodyweight and training goal.Bandage Stock Calculator
Home bandage stock from household size and annual usage.Swim Cap Life Calculator
Swim cap replacement months from weekly swims and material lifespan.Headphone Safe Time Calculator
Safe listening duration from headphone volume via 3dB exchange rate.Stair Calories Calculator
Calories burned climbing stairs by floors and body weight.Cane Height Calculator
Cane grip height from body weight ratio.Braces Duration Calculator
Clear aligner treatment duration from tray count and wear days.4-7-8 Breathing Calculator
Total 4-7-8 breathing session time from cycle rounds.Arch Type Calculator
Arch type from wet footprint midfoot ratio with insole advice.Nasal Spray Duration Calculator
Days of supply from sprays per bottle and daily usage.First Aid Kit Calculator
First aid kit item count from household size, kids and pets.Sanitary Pad Calculator
Monthly pad or tampon count from day and night usage habits.Compression Sock Size Calculator
Compression sock size from ankle and calf circumference.Meditation Weekly Calculator
Weekly meditation minutes from session length.Foot Soak Calculator
Weekly foot-soak minutes from sessions.Voice Load Calculator
Speaking load and voice rest from sessions.Reading Glasses Power Calculator
Reading add power by age reference.Hearing Aid Battery Calculator
Hearing aid battery days by model and wear time.Trekking Pole Calculator
Trekking pole length by body height.Ski Length Calculator
Ski length by height and skill level.Ear Temperature Calculator
Core temperature from ear reading.Grip Strength Calculator
Grip strength index from grip and weight.Lung Capacity Calculator
Lung capacity index from volume and weight.Bike Saddle Width Calculator
Bike saddle width by sit bone distance.Steam Eye Mask Calculator
Steam eye mask usage by sessions per week.Dust Mite Vacuum Calculator
Total anti-mite cleaning time by mattress area.Magnesium Intake Calculator
Daily magnesium intake by body weight.Kegel Exercise Calculator
Daily Kegel training volume by sets and reps.Lumbar Pillow Calculator
Lumbar pillow thickness by seat depth.Night Light Calculator
Night light lumens by bedroom size.Kettlebell Weight Calculator
Starter kettlebell weight by body weight.Jump Box Calculator
Plyo box height by athlete height.Knee Brace Size Calculator
Knee brace size by knee circumference.Wrist Brace Size Calculator
Wrist brace size by wrist circumference.Ankle Brace Size Calculator
Ankle brace size by ankle circumference.Creatine Daily Dose Calculator
Daily creatine dose by body weight.Layering System Calculator
Clothing layers by temperature.Pulse Oximeter Reading Calculator
SpO2 reading grade and guidance.Bandage Length Calculator
Bandage length by wrap count.IV Drip Rate Calculator
Drip rate by volume and time.Sit and Reach Calculator
Sit-and-reach flexibility grade.Ruler Drop Reaction Time Calculator
Reaction time from catch distance.Bone Density T-Score Calculator
T-score classification.Gait Speed Calculator
Walking speed over 6 meters.Respiratory Rate Calculator
Breathing rate assessment.Single-Leg Stance Calculator
Balance seconds by age.30-Second Sit-to-Stand Calculator
Leg strength by reps in 30 s.Heart Rate Recovery Calculator
HRR by 1-min heart rate drop.6-Minute Walk Calculator
Endurance grade by walked distance.TUG Test Calculator
Fall risk by timed up-and-go.Sleep Quality Score Calculator
Score by sleep latency and wakes.Calf Circumference Screen Calculator
Sarcopenia screen by calf girth.30-Second Arm Curl Calculator
Upper-body grade by curls.Head-to-Wall Posture Test
Forward head test by gap.Breath Hold Test
Breath hold by seconds.Heel Raise Test
Calf endurance by reps.Sit-Up Test
Core endurance by reps.Wall Squat Test
Isometric endurance by seconds.Eye Drop Calculator
Days by drops.Crutch Height Calculator
Crutch length by height.Wheelchair Seat Calculator
Seat width by hip.Heat Stroke Risk
Risk by temperature and humidity.Heat Compress Calculator
Compress time by body part.Pill Splitter Calculator
Days by dose.Ankle Pump Calculator
Reps by sets.Leg Elevation Calculator
Height by need.Fish Oil Calculator
Capsules by omega-3 need.Painkiller Limit Calculator
Daily max by interval.Elbow Brace Size Calculator
Brace size by elbow girth.Neck Brace Size Calculator
Collar size by neck girth.Massage Gun Calculator
Minutes by body part.Glute Bridge Calculator
Reps by sets.Motion Sickness Timing Calculator
Dose timing by transport.Pull-up Volume Calculator
Reps by sets.Alcohol Standard Drink Calculator
Standard drinks by volume.Dental Cleaning Cost Calculator
Yearly cost by visits.Lens Index Calculator
Index by prescription.Standing Jump Score Calculator
Score by jump distance.Related Guides
BMI Standard Ranges: Formula, Tables & Limitations
BMI = weight(kg) ÷ height(m)². Chinese standard: 18.5–23.9 normal, 24–27.9 overweight, ≥28 obese. WHO uses 25/30 cutoffs. Includes full classification tables, examples at common heights, and why muscular people and the elderly should read BMI with caution.
Daily Calorie Needs: BMR, TDEE & Deficit Planning
Daily burn (TDEE) = BMR × activity factor (1.2–1.9). A 30-year-old office worker at 70kg burns ~2,000–2,200 kcal/day. Fat loss: eat 300–500 kcal below TDEE for ~0.5kg/week. Includes Mifflin-St Jeor formula, activity tables and plateau troubleshooting.
Ideal Weight: Standard Formulas & Healthy Ranges
Common formulas: Broca (height−105 for men, −110 for women), BMI-based range (18.5–23.9 × height²), and Devine. A 175cm man's ideal range is ~57–73kg. Why a range beats a single number, and how frame size and muscle mass shift your personal target.
Waist-to-Hip Ratio: Standards, Measurement & Health Risk
WHR = waist ÷ hip. Risk thresholds: men >0.90, women >0.85 (WHO). Apple shape (high WHR) carries 2–3× the cardiovascular risk of pear shape at the same BMI. Measurement technique, percentile tables and reduction strategies inside.
Body Fat Percentage: Formulas, Standards & Measurement
Healthy ranges: men 10-20%, women 18-28% (varies by age). Navy formula uses waist/neck/height (±3-4%); DEXA is the lab gold standard. Covers all measurement methods, age-adjusted tables, and why BMI misses skinny-fat.
Waist-to-Hip Ratio: How to Measure, Standards & Health Risk
WHR = waist ÷ hip. Risk lines: men >0.90, women >0.85 (WHO). Measure waist at the navel, hips at the widest point, standing relaxed. Apple vs pear shape, the WHtR alternative (waist ÷ height < 0.5), and how to improve.