Health & everyday tools
Body metrics, training numbers and everyday estimates — educational calculators, not medical advice.
Most popular
Antibiotic Resistance Evolution Simulator
Watch bacteria evolve resistance — and see why finishing the course matters.
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BMI Calculator
Body mass index, WHO category and healthy weight range.
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BMR & TDEE Calculator
Resting calories and daily energy needs by activity level.
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Blood Alcohol Estimator
Widmark BAC estimate and hours until sober.
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Caffeine Half-Life Visualizer
How much caffeine is still in you at bedtime.
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Calories Burned Calculator
Energy burned by activity using MET values.
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Child Growth Percentile Calculator
WHO percentile for a child's weight, height or head size.
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Drug Half-Life & Dosing Simulator
Plot how a drug builds up and washes out of your body across a full dosing schedule.
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Dynamic Weight Change Simulator
Realistic weight trajectory with metabolic adaptation.
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Herd Immunity Threshold Explorer
See how vaccinating enough people stops an outbreak for everyone.
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Ideal Weight Calculator
Devine, Robinson, Miller and Hamwi targets plus BMI range.
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Macro Calculator
Protein, carb and fat grams from your daily calories.
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One-Rep Max Calculator
Estimate your 1RM from reps, with a %-load table.
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Ovulation & Fertility Calculator
Fertile window and ovulation for the next six cycles.
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Pregnancy Due Date Calculator
Due date from last period, conception or IVF transfer.
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Running Pace Calculator
Pace ↔ speed ↔ race time, plus a race predictor.
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Sleep Cycle Calculator
Bedtimes or alarms aligned to 90-minute sleep cycles.
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Water Intake Calculator
Daily fluid target from weight, exercise and climate.
Body & Metabolism
BMI Calculator
Body mass index, WHO category and healthy weight range.
popular
BMR & TDEE Calculator
Resting calories and daily energy needs by activity level.
popular
Child Growth Percentile Calculator
WHO percentile for a child's weight, height or head size.
popular
Dynamic Weight Change Simulator
Realistic weight trajectory with metabolic adaptation.
popular
Ideal Weight Calculator
Devine, Robinson, Miller and Hamwi targets plus BMI range.
popular
Macro Calculator
Protein, carb and fat grams from your daily calories.
Body Fat Estimator (Navy Method)
Body fat percent from tape measurements only.
Body Surface Area Calculator
BSA in m² by Mosteller, Du Bois and three more formulas.
Waist-to-Hip & Waist-to-Height Calculator
Body-shape risk from waist, hip and height.
Everyday Health
Antibiotic Resistance Evolution Simulator
Watch bacteria evolve resistance — and see why finishing the course matters.
popular
Blood Alcohol Estimator
Widmark BAC estimate and hours until sober.
popular
Drug Half-Life & Dosing Simulator
Plot how a drug builds up and washes out of your body across a full dosing schedule.
popular
Herd Immunity Threshold Explorer
See how vaccinating enough people stops an outbreak for everyone.
popular
Ovulation & Fertility Calculator
Fertile window and ovulation for the next six cycles.
popular
Pregnancy Due Date Calculator
Due date from last period, conception or IVF transfer.
popular
Water Intake Calculator
Daily fluid target from weight, exercise and climate.
Blood Pressure Category Calculator
Classify a reading by the AHA categories.
Dose & Rate Converter
mg/kg doses, mg to mL volumes and infusion rates.
Pregnancy Weight Gain Calculator
Recommended gain from pre-pregnancy BMI (IOM).
Fitness & Training
Calories Burned Calculator
Energy burned by activity using MET values.
popular
One-Rep Max Calculator
Estimate your 1RM from reps, with a %-load table.
popular
Running Pace Calculator
Pace ↔ speed ↔ race time, plus a race predictor.
Heart Rate Zone Calculator
Five training zones from age or measured max HR.
VO₂max Estimator
Aerobic fitness from a Cooper, heart-rate or run test.
Sleep & Stimulants
About these tools
Everyday health calculators for quick, practical answers: body mass index, calorie needs, running pace, target heart rate, sleep cycles and hydration. The results are educational estimates based on published formulas — useful for orientation and tracking trends, but never a substitute for advice from a doctor or dietitian.