Health Calculators
Your health numbers make more sense with context. These tools turn height, weight, age and activity into clear ranges and daily targets using widely used formulas — for information and planning, never as medical advice.
BMI Calculator
Body mass index from height and weight, with the healthy weight range for your height.
Open toolCalorie Calculator
Daily calories to maintain, lose or gain weight, based on your activity level.
Open toolBody Fat Calculator
Estimate body fat percentage from your measurements using the U.S. Navy method.
Open toolMacro Calculator
Daily protein, carb and fat targets split to match your goal.
Open toolTDEE Calculator
Total daily energy expenditure — the calories you burn on an average day.
Open toolIdeal Weight Calculator
Healthy weight ranges for your height from several established formulas.
Open toolWater Intake Calculator
How much water you should drink each day for your weight and activity.
Open toolProtein Calculator
Daily protein needs for sedentary, active and muscle-building lifestyles.
Open toolHeart Rate Zone Calculator
Your five training zones from your age and resting heart rate.
Open toolPace Calculator
Running pace per mile or kilometer, finish times and splits.
Open toolSleep Calculator
Wake-up and bedtime suggestions built on full 90-minute sleep cycles.
Open toolOvulation Calculator
Your fertile window and estimated ovulation day from your cycle.
Open toolDue Date Calculator
An estimated baby due date from your last period or conception date.
Open toolPeriod Calculator
Your next period, ovulation day and fertile window from your last period and cycle length.
Open toolPregnancy Calculator
How far along you are today, your due date and the milestone dates of your pregnancy.
Open toolConception Calculator
The most likely conception date and window, worked out from your last period or your due date.
Open toolOne Rep Max Calculator
Your one-rep max from any set, by the Epley and Brzycki formulas, with a full percentage table.
Open toolBAC Calculator
A Widmark estimate of blood alcohol from drinks, weight and time — an estimate only, never a safe-to-drive test.
Open toolBMR Calculator
Your basal metabolic rate from the Mifflin-St Jeor equation — the calories your body burns at rest, with activity levels.
Open toolCalorie Deficit Calculator
A daily calorie target for your goal weight, with the estimated weeks to get there at a chosen deficit.
Open toolCalories Burned Calculator
Calories burned by walking, running, cycling, swimming and more, from MET values, your weight and minutes.
Open toolLean Body Mass Calculator
Your lean body mass by the Boer, James and Hume formulas — the weight that is not body fat.
Open toolWaist-to-Hip Ratio Calculator
Your waist-to-hip ratio and where it sits against WHO risk bands for your sex.
Open toolBody Surface Area Calculator
Body surface area in m² by the Mosteller and Du Bois formulas — the number used in clinical dosing.
Open toolPregnancy Weight Gain Calculator
IOM-recommended weight gain for your pre-pregnancy BMI — total range and the expected range at your week.
Open toolKids BMI Calculator
BMI percentile for children and teens aged 2–19, using the CDC BMI-for-age growth charts.
Open toolSteps to Miles Calculator
Turn steps into miles and kilometres using your height or stride length, with an estimated calorie burn.
Open toolHealth numbers, honestly explained
Health calculators give estimates, not verdicts. Every tool in this section names the formula it uses — Mifflin-St Jeor for calories and TDEE, the US Navy tape method for body fat, standard 90-minute cycles for sleep — and shows the healthy range around your result, so you can see where a number sits instead of just staring at it.
Start with the BMI Calculator for a first screening, then go deeper: the Calorie Calculator turns your stats into daily targets for maintaining, losing or gaining, and the Macro Calculator splits that target into protein, carbs and fat. Treat every result as a starting point for a conversation with your doctor or dietitian, especially for pregnancy, fertility and heart-rate training.
For cycles and pregnancy, the Period Calculator forecasts your next three cycles with ovulation and fertile-window dates, and the Pregnancy Calculator answers “how far along am I?” with your due date and milestone dates — estimates to discuss with your clinician, never a substitute for one. The Conception Calculator works the same calendar backwards to a most likely conception date, from either your last period or your due date.
For training, the One Rep Max Calculator turns any hard set into an estimated 1RM by two established formulas, with the percentage table coaches program from. And the BAC Calculator gives a Widmark estimate of blood alcohol after drinking — useful for understanding how alcohol leaves the body, and always paired with the only safe rule: never drive after drinking.
The newest tools go one level deeper. The BMR Calculator isolates your resting burn before any activity multiplier, and the Calorie Deficit Calculator turns a goal weight into a daily target with an honest time estimate. Activity itself is priced by the Calories Burned Calculator (MET-based) and the Steps to Miles Calculator. Body composition estimates include Lean Body Mass, the Waist-to-Hip Ratio and Body Surface Area. For families: the Pregnancy Weight Gain Calculator follows IOM ranges by pre-pregnancy BMI, and the Kids BMI Calculator uses CDC BMI-for-age percentiles — because children's BMI is read against growth charts, never adult cut-offs.