Health calculators

Health and fitness calculators for BMI, calories, body fat, nutrition, and exercise. Based on established clinical formulas — useful for a reliable starting point, not a substitute for professional medical advice.

21 calculators

• Adult Height Predictor

  Estimate a child's likely adult height from the parents using the Tanner mid-parental method, with a 95% range so you can see how much the prediction varies.

• Army Body Fat Calculator

  Estimate your body-fat percentage with the US Army tape test (Hodgdon-Beckett, DA Form 5500/5501) and see how it compares to the AR 600-9 maximum for your age.

• BMI Calculator

  Calculate your body mass index from weight and height and see where you sit on the World Health Organization adult BMI scale.

• BMR Calculator

  Estimate your basal metabolic rate — the calories your body burns at complete rest — using the Mifflin-St Jeor equation, the modern reference standard for healthy adults.

• Body Fat Percentage Calculator

  Estimate your body fat percentage from tape-measure circumferences using the U.S. Navy method — no calipers, no expensive scans.

• Body Surface Area (BSA) Calculator

  Enter your height and weight to get your body surface area in square metres, computed by the five major published formulas — Mosteller (clinical default), DuBois, Haycock, Gehan & George and Boyd.

• Calorie Calculator

  Enter your sex, age, weight, height and activity level. The calculator returns BMR, daily maintenance calories, a cutting target (-500 kcal) and a lean-bulk target (+300 kcal).

• Calories Burned Calculator

  Pick an activity, type your body weight and how long you trained. The calculator returns total kcal burned plus per-hour and per-minute rates using MET values from the published Compendium of Physical Activities.

• Carbohydrate Intake Calculator

  Enter your daily calories (TDEE) and a target carb percentage to get grams of carbohydrate per day. Defaults follow the Institute of Medicine’s Acceptable Macronutrient Distribution Range of 45-65 % of total calories from carbs.

• Daily Water Intake Calculator

  Estimate how much water you need each day based on body weight, exercise and climate, using the 35 mL/kg clinical baseline and ACSM exercise additions.

• Fat Intake Calculator

  Enter your daily calories (TDEE) and a target fat percentage to get grams of dietary fat per day. Defaults follow the Institute of Medicine’s Acceptable Macronutrient Distribution Range of 20-35 % of total calories from fat.

• Healthy Weight Calculator

  Find the weight range that puts you in the World Health Organization healthy BMI band for your height, in kilograms or pounds.

• Lean Body Mass Calculator

  Estimate your lean body mass using three published equations — Boer, James and Hume — and see the implied body fat percentage.

• Overweight Calculator

  Find out how far above the World Health Organization healthy BMI band you are, in kilograms or pounds.

• Period Calculator

  Predict your next period, ovulation day and fertile window from the first day of your last period and your usual cycle length.

• Pregnancy Due Date Calculator

  Estimate your estimated due date (EDD) and trimester milestones using Naegele’s rule — the 40-week (280-day) standard adopted by ACOG and used by midwives and obstetricians worldwide.

• Pregnancy Weight Gain Calculator

  Compare your weight gain so far against the Institute of Medicine recommended range for your pre-pregnancy BMI and pregnancy week.

• Protein Calculator

  Enter your body weight (kg or lb) and pick an activity level to get your daily protein target in grams. Targets follow the Institute of Medicine RDA for sedentary adults and the ACSM, Academy of Nutrition and Dietetics, Dietitians of Canada and ISSN positions for athletes.

• Running Pace Calculator

  Enter the distance and time of any run to see your pace per kilometre and per mile, speed in km/h and mph, and projected finish times at the standard race distances — 5K, 10K, half marathon and marathon.

• Sleep Calculator

  Pick whether you want to wake up at a target time or go to bed at a target time. The calculator works backward or forward in 90-minute sleep cycles so you wake at the end of a cycle — not stuck in deep sleep.

• TDEE Calculator

  Estimate the calories you burn in a typical day. The calculator splits TDEE into resting metabolism (BMR) plus activity burn so you can see where the kcal go.