Health calculators

Estimate blood alcohol content using the Widmark formula. Enter drinks consumed, body weight, and time elapsed to get an estimated BAC percentage.

Calculate your body mass index from height and weight in imperial or metric units, with CDC weight classification and healthy weight range for your height.

Calculate your Basal Metabolic Rate using three formulas — Mifflin-St Jeor, Harris-Benedict (revised), and Katch-McArdle (requires body fat %) — in imperial or metric units.

Estimate your body fat percentage using the US Navy circumference method. Enter height, neck, waist, and hip measurements to get body fat %, fat mass, lean mass, and a fitness category.

Estimate daily calorie needs using the Mifflin-St Jeor BMR formula with your activity level and weight goal. Includes macro breakdown for protein, carbs, and fat.

Estimate calories burned during exercise using MET values from the Compendium of Physical Activities. Covers 25+ activities.

Calculate your daily protein intake target from body weight, activity level, and goal — maintain, muscle gain, or weight loss. Results show total grams, per-meal amount, and g/kg rate.

Calculate your recommended daily water intake from body weight, activity level, and climate. Results in liters, fluid ounces, cups, and milliliters.

Calculate gestational age in weeks and days from your last menstrual period (LMP) or from a known ultrasound measurement. Shows due date, trimester, days until delivery, and upcoming milestones.

Calculate your 5 heart rate training zones using the Karvonen heart rate reserve method or simple percentage of max HR, based on your age and resting heart rate.

Find your ideal body weight using four evidence-based formulas — Devine, Robinson, Miller, and Hamwi. See the average, the full range, and a side-by-side formula comparison.

Estimate your lean body mass (LBM) using the Boer, James, and Hume formulas. Optionally enter body fat percentage for a direct measurement.

Calculate your daily protein, carbohydrate, and fat targets in grams from your calorie goal, body weight, and fitness goal.

Calculate your maximum heart rate using four formulas — Standard (220−age), Tanaka, Gulati, and Fox — and see target heart rate zones for any intensity level.

Calculate your ovulation date, fertile window, and next period from your last menstrual period date, cycle length, and luteal phase. See how many days until ovulation and whether you are currently in your fertile window.

Track and predict your next periods, ovulation dates, and fertile windows for up to 6 future cycles. Enter your last period date, cycle length, and period duration to see your full menstrual cycle calendar.

Estimate your due date using Naegele's rule from the first day of your last period or conception date. Shows gestational week, trimester, days remaining, and progress.

Predict finish times for 1 mile, 5K, 10K, half marathon, and marathon from any known race performance using the Riegel formula.

Calculate your running pace per mile or per kilometer, speed in mph and kph, and projected finish times for common race distances.

Find the ideal bedtime or wake time based on 90-minute sleep cycles. Enter when you need to wake up or when you plan to go to bed to get recommendations for 5, 5.5, or 6 complete sleep cycles.

Calculate Total Daily Energy Expenditure from your BMR and activity level. Set a weight goal to get your calorie target and macro breakdown.

Estimate your VO2 max from a Rockport walk test, Cooper 12-minute run, resting heart rate, or 1.5-mile run. Shows fitness category and approximate percentile.

Calculate your waist-to-hip ratio (WHR) and find your cardiovascular risk category using World Health Organization thresholds.