Fitness, body and nutrition calculators. — 43 free tools.
Calculate BMI with category, ideal weight range, body fat estimate and lean body mass in metric or imperial units.
★Calculate BMR using Mifflin-St Jeor, Harris-Benedict or Katch-McArdle, plus TDEE and calorie targets for your goal.
★Calculate daily calories for weight loss, maintenance or gain with macro split (protein/carbs/fat) and goal timeline.
★Estimate body fat percentage using the US Navy tape method.
★Estimate ideal body weight from height using Devine and Robinson formulas.
★Find how much water you should drink each day based on weight and activity.
★Calculate your daily protein target based on weight and goal.
★Find your maximum and target heart-rate training zones.
★Calculate your running pace per km and speed from distance and time.
★Estimate your one-rep max from the weight and reps you lifted.
★Estimate your pregnancy due date from your last menstrual period.
★Calculate body mass index using height and weight.
★Calculate BMI from pounds and inches.
★Estimate basal metabolic rate (Mifflin-St Jeor).
★Estimate total daily energy expenditure.
★Estimate body fat percentage using the US Navy method.
★Estimate lean body mass.
★Estimate ideal body weight (Devine formula).
★Estimate calories burned during exercise from MET value.
★Split daily calories into protein, carbs and fat.
★Estimate recommended daily water intake.
★Find the daily deficit to reach a weight-loss goal.
★Estimate daily protein requirement.
★Calculate waist-to-hip ratio and risk level.
★Calculate waist-to-height ratio.
★Find your target heart-rate training zones.
★Estimate maximum heart rate by age.
★Estimate a due date from the last menstrual period.
★Estimate ovulation and fertile window.
★Predict a child’s adult height from parents’ heights.
★Estimate body surface area (Mosteller).
★Find daily calories for losing, maintaining or gaining weight.
★Calculate units of alcohol in a drink.
★See how much smoking costs you over time.
★Find ideal bedtimes based on 90-minute sleep cycles.
★Estimate total body water percentage.
★Calculate the ponderal (corpulence) index.
★Estimate total blood volume (Nadler).
★Estimate VO2 max from a 1.
★Convert your step count into calories burned.
★Estimate time lost from smoking (11 min per cigarette).
★Estimate calories burned at rest per day.
★Calculate smoking pack-years for health screening.
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Author: CalculatorFC Editorial Team
Reviewed by: CalculatorFC Accuracy Review Desk
Last updated: June 23, 2026
Editorial policy: We explain formulas, assumptions, limitations and examples in plain language and update pages when methods, rates or standards change.
Fact-checking policy: Calculator formulas are reviewed against standard mathematical, financial, scientific or public reference methods where applicable.
Sources: Standard formulas, official government references where relevant, public methodology references and calculator-specific documentation.
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