Health calculators

135 free health tools, each with the formula and step-by-step working.

• A1C CalculatorConvert A1C to average blood glucose.
• A1C to Average Glucose Calculator (ADAG)Convert HbA1c to estimated average glucose.
• Adjusted Body Weight CalculatorIBW and adjusted weight for dosing.
• Alcohol BAC Timeline CalculatorBlood alcohol level and time to sober up.
• Alcohol Calories CalculatorCalories in your weekly drinks, and what that costs.
• Alcohol Units CalculatorUnits and standard drinks in a beverage.
• Anion Gap CalculatorAnion gap with albumin correction and delta ratio.
• Baby Formula Intake CalculatorEstimate daily formula volume by weight.
• Baby Milk Intake CalculatorDaily milk volume a baby needs by weight.
• Baby Weight Percentile CalculatorWhere your baby's weight sits.
• BAC Sober Time CalculatorEstimate blood alcohol and how many hours until you are back to zero.
• Blood Alcohol CalculatorEstimated BAC and hours until sober.
• Blood Pressure CalculatorCategory, MAP and pulse pressure.
• Blue Light Bedtime CalculatorWhen to stop screens before bed for better sleep.
• BMI CalculatorBody mass index with the healthy weight range for your height.
• BMI Prime CalculatorYour BMI as a simple ratio to the upper healthy limit.
• BMR CalculatorCalories your body burns at complete rest.
• BMR Formula Comparison CalculatorCompare Mifflin-St Jeor, Harris-Benedict and Katch-McArdle.
• Body Fat CalculatorUS Navy method body fat from tape measurements.
• Body Fat Tape Measure Calculator (YMCA Method)Quick body fat estimate from weight and waist.
• Body Surface Area CalculatorBSA by Mosteller, Du Bois and Haycock formulas.
• BSA-Based Medication Dosing CalculatorDose from body surface area (Du Bois formula).
• Caffeine Half-Life CalculatorSee how much caffeine is still in your system at bedtime.
• Caffeine Limit CalculatorYour safe daily caffeine ceiling and how many coffees or energy drinks that is.
• Calorie Cycling CalculatorHigher calories on training days, lower on rest days.
• Calorie Deficit CalculatorDaily calories to lose a target amount by a chosen date.
• Calorie Deficit Timeline CalculatorTime to reach a weight goal from your daily deficit.
• Calories Burned CalculatorEnergy burnt in any activity using MET values.
• Carb CalculatorDaily carbohydrate target.
• Carb Target CalculatorDaily carbohydrate target from calories and macros.
• Child BMI CalculatorBMI and category for children.
• Child Calorie Needs CalculatorDaily energy needs for children by age and activity.
• Child Growth Percentile Calculator (LMS Approximation)Approximate weight-for-age percentile for children.
• Cholesterol Ratio CalculatorTotal to HDL ratio and LDL estimate.
• Cholesterol Ratio Risk CalculatorTotal/HDL and LDL/HDL ratios with risk bands.
• Circadian Jet Lag Adjustment CalculatorHow many days to adjust, and when to seek light.
• Coffee Caffeine Content CalculatorTotal daily caffeine across every drink you have.
• Corrected Calcium CalculatorCalcium adjusted for low albumin.
• Creatinine Clearance CalculatorCockcroft-Gault kidney function.
• Daily Potassium Intake Target CalculatorRecommended potassium intake by body weight.
• Daily Water Goal CalculatorFluid target adjusted for exercise and climate.
• Daily Water Intake CalculatorHow much to drink for your weight, climate and training.
• Days Supply CalculatorPharmacy days-supply for tablets, liquids, inhalers and insulin.
• Dental Implant Cost CalculatorImplant, abutment, crown and extras with insurance.
• Due Date CalculatorEstimated delivery date and pregnancy milestones.
• eGFR CalculatorKidney function estimate from serum creatinine.
• eGFR Calculator (MDRD Equation)Estimate kidney filtration rate from creatinine.
• Electrolyte CalculatorSodium, potassium and magnesium replacement for long or hot sessions.
• Fat Target CalculatorDaily dietary fat target from calories.
• FENa CalculatorDistinguish prerenal from intrinsic renal azotemia in seconds.
• Fiber Goal by Calorie Intake CalculatorDaily fiber target scaled to calorie intake.
• Fiber Intake CalculatorDaily fibre target and your gap.
• Fiber Per Meal CalculatorDaily fibre target split across your meals.
• Gestational Age CalculatorWeeks pregnant from LMP.
• Glucose Conversion Calculatormg/dL to mmol/L blood sugar.
• Goal Weight Calorie CalculatorCalories to maintain your target weight.
• Goal Weight Date CalculatorWhen you'll hit your target at your current rate.
• Goal Weight Date CalculatorEstimate the date you will hit a goal weight.
• Heart Rate Zone CalculatorFive training zones from your max and resting heart rate.
• Hydration CalculatorDaily water target adjusted for exercise, heat and body size.
• Ideal Body Weight CalculatorCompare Devine, Robinson and Miller formulas.
• Ideal Weight CalculatorFour classic formulas plus the healthy BMI range.
• Infant Growth Percentile CalculatorWeight, length and head circumference percentiles for babies 0-24 months.
• Insulin Dose CalculatorMeal bolus and correction dose.
• Insulin Sensitivity Factor Calculator (1800 Rule)Estimate correction factor from total daily insulin dose.
• Intermittent Fasting CalculatorFasting and eating window schedule.
• Intermittent Fasting Window CalculatorEating and fasting window from your schedule.
• Iron Intake CalculatorDaily iron target by age, sex and diet type.
• IV Drip Rate CalculatorDrops per minute for an infusion.
• Keto Macro CalculatorKetogenic fat, protein and carb split.
• LDL Cholesterol Calculator (Friedewald Equation)Estimate LDL from total, HDL and triglycerides.
• Lean Body Mass CalculatorEverything that isn't fat: muscle, bone, organs and water.
• Lean Body Mass Calculator (Boer Formula)Estimate fat-free mass from height and weight.
• Macro CalculatorProtein, carbs and fat grams for your calorie target.
• Macro Calculator by GoalProtein, carb and fat grams for cut, maintain or bulk.
• Macro Split CalculatorTurn daily calories into protein, carb and fat grams.
• Meal Calorie CalculatorCalories from macros in a meal.
• Meal Prep Portion CalculatorScale a recipe to hit per-portion calorie targets.
• Mean Arterial Pressure CalculatorCalculate MAP from systolic and diastolic BP.
• Medication Dose by Weight CalculatorWeight-based dosing with volume per dose.
• Medication Half-Life CalculatorRemaining drug concentration over time.
• Metabolic Age CalculatorCompare your BMR to age norms.
• METs CalculatorExercise intensity and calories from METs.
• Midparental Height CalculatorPredicted adult height from parents' heights.
• Nap Length CalculatorPick a nap length that avoids grogginess.
• Navy Body Fat CalculatorBody fat percentage from tape measurements.
• One Rep Max CalculatorEstimated 1RM plus a full percentage training table.
• Ovulation CalculatorFertile window and ovulation day from your cycle.
• Ovulation Window CalculatorEstimate fertile window from cycle length.
• Pack Year CalculatorSmoking history in pack years.
• Pediatric Dose CalculatorWeight-based dosing for children.
• Pediatric Weight-Based Dosing Calculatormg/kg dose from body weight.
• Percentage Weight Lost CalculatorPercent change between starting and current weight.
• Ponderal Index CalculatorA height-cubed alternative to BMI.
• Posture Break CalculatorSchedule movement breaks across a work day.
• Pregnancy Due Date CalculatorDue date and trimester milestones from your last period.
• Pregnancy Trimester CalculatorTrimester dates, current week and countdown from your last period or due date.
• Pregnancy Weight Gain by Week CalculatorExpected weight gain range by gestational week.
• Pregnancy Weight Gain CalculatorRecommended gain by BMI and week.
• Protein Intake CalculatorDaily protein target based on weight and training.
• Protein Per Meal CalculatorSplit your daily protein target across meals for maximum muscle protein synthesis.
• Protein Target CalculatorDaily protein target by body weight and goal.
• Pulse Pressure CalculatorDifference between systolic and diastolic.
• Resting Metabolic Rate CalculatorRMR from Mifflin-St Jeor, Harris-Benedict and Katch-McArdle side by side.
• Rucking Calorie CalculatorCalories burned rucking, using the Pandolf load-carriage equation.
• Running Pace CalculatorPace, finish time and splits for any distance.
• Sauna Calorie CalculatorEstimate calories burned during a sauna session from weight, temperature and time.
• Screen Time CalculatorDaily screen hours turned into days per year.
• Skinfold Body Fat Calculator (Jackson-Pollock 3-Site)Body fat from 3-site skinfold measurements.
• Sleep CalculatorBest bedtimes and wake times by sleep cycle.
• Sleep Cycle CalculatorBedtimes that let you wake between cycles, not mid-cycle.
• Sleep Debt CalculatorHow much sleep you owe and how to repay it.
• Sodium Correction CalculatorCorrected sodium for hyperglycaemia.
• Sodium Intake CalculatorTrack sodium against guideline limits and convert salt to sodium.
• Sodium-to-Potassium Ratio CalculatorDietary sodium/potassium balance.
• Standing Desk Calorie CalculatorExtra calories burned by standing instead of sitting.
• Steps to Miles CalculatorConvert step count to distance and calories.
• Sugar Intake CalculatorAdded sugar in grams, teaspoons and % of calories.
• Sweat Rate CalculatorFluid lost per hour, and what to drink back.
• TDEE Activity Multiplier CalculatorTotal daily energy expenditure by activity level.
• TDEE CalculatorTotal daily energy expenditure and macro targets.
• Vitamin D CalculatorDose to reach a target blood level.
• Vitamin D Dose CalculatorDaily IU needed based on weight and sun exposure.
• Vitamin D Sun Exposure CalculatorEstimate vitamin D synthesis from sun exposure.
• VO2 Max CalculatorAerobic fitness from a 1.5-mile run or Cooper test.
• Waist to Height Ratio CalculatorA better risk marker than BMI, in one measurement.
• Waist to Height Ratio CalculatorA better risk screen than BMI: keep your waist under half your height.
• Waist to Hip Ratio CalculatorBody shape and health risk.
• Waist-to-Height Ratio CalculatorCentral obesity risk from waist and height.
• Wake Up Time CalculatorBest bedtimes based on 90-minute sleep cycles.
• Walking Time CalculatorHow long a walk takes at your pace, including hills.
• Water Intake Calculator by Body WeightDaily water target from weight and activity.
• Weight Loss Percentage CalculatorPercent of body weight lost.
• Weight Loss Timeline CalculatorRealistic date to reach your goal weight.
• Wilks Score CalculatorCompare powerlifting totals across bodyweights.

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