Health & Fitness calculators
These calculators turn a few measurements into a standard figure: a body mass index, a daily calorie estimate, a running pace, a due date. They are good for spotting a trend over time or preparing questions for a doctor, coach, or dietitian, and they are not a diagnosis.
Every health and fitness tool names the formula it uses, the people that formula was built from, and the situations where it is known to mislead, such as body mass index for very muscular athletes.
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- BMI CalculatorCalculate adult body mass index from height and weight in US or metric units, with the adult category and the healthy weight range for your height.
- BMR CalculatorFind out how many calories your body burns at rest with the Mifflin-St Jeor, Harris-Benedict or Katch-McArdle formula, plus your daily needs by activity level.
- Body Fat CalculatorEstimate your body fat percentage, fat mass and lean mass from a few tape measurements using the U.S. Navy method, with the ACE chart band and a BMI-based comparison.
- Calorie CalculatorFind out how many calories you need each day (your TDEE) to keep your weight steady, plus daily targets for losing or gaining weight slowly.
- Ideal Weight CalculatorSee what four well-known ideal weight formulas (Devine, Robinson, Miller and Hamwi) give for your height, next to the healthy-BMI weight range.
- Ovulation CalculatorEstimate your ovulation day, fertile window, most fertile days, next period and pregnancy test date from your last period and usual cycle length.
- Pace CalculatorFind your running pace, finish time or distance from the other two. See your speed and finish times for common races.
- Period CalculatorEstimate when your next periods will start and end for the next six cycles, from your last period and your cycle length or past start dates.
- Pregnancy Due Date CalculatorEstimate your baby's due date from your last period, conception, an IVF transfer or an ultrasound, with weeks pregnant, trimester and key milestone dates.
- Army Body Fat CalculatorCheck the US Army's current waist-to-height ratio standard (below 0.55) and see the former one-site tape-test body fat estimate it replaced.
- Calorie Deficit CalculatorGet a rough idea of how long it might take to reach a goal weight if you eat the same amount below your needs every day.
- Calories Burned CalculatorEstimate the calories you burn during an activity from its MET value, your body weight and the duration.
- Conception Date CalculatorFind out when conception most likely happened, from your due date or last period, or count forward from a conception date to a due date.
- Heart Rate Zones CalculatorEstimate your maximum heart rate and five training zones, either as a percentage of maximum or by the Karvonen heart-rate reserve method.
- Lean Body Mass CalculatorEstimate how much of your weight is not fat, from your sex, height and weight, using the Boer, James and Hume formulas.
- One Rep Max CalculatorEstimate your one-rep max from a weight and the number of reps you completed, with a training-load table from 50% to 100%.
- Protein CalculatorGet a general idea of how many grams of protein a day suit your body weight and how active you are.
- Sleep Cycle CalculatorFind bedtimes or wake-up times that line up with whole sleep cycles of about 90 minutes.
- Water Intake CalculatorGet a rough idea of how much to drink each day from your body weight, with extra for exercise and hot weather if you need it.
- Barbell Plate CalculatorSee which plates to load on each side of a barbell to reach your target weight, in pounds or kilograms, using the plate sizes you actually have.
- Body Surface Area CalculatorEstimate body surface area, the total area of your skin, from height and weight using the Mosteller, DuBois, Haycock or Boyd formula.
- Caffeine Intake CalculatorAdd up the caffeine in the coffee, tea, soft drinks and energy drinks you have in a day and compare the total with a daily limit you choose.
- Child Height PredictorEstimate how tall a child may be as an adult from the parents' heights, using the mid-parental (Tanner) method, with the usual range around it.
- FFMI CalculatorSee how much lean mass you carry for your height (your FFMI), plus a height-adjusted version, from height, weight and body fat.
- Hiking Time CalculatorFind out how long a hike will take from its distance and how much you climb, using Naismith's rule, with optional downhill corrections, pace adjustment and breaks.
- Implantation Date CalculatorEstimate when implantation would most likely happen, from an ovulation date or the first day of your last period. See when a home pregnancy test is most reliable.
- Intermittent Fasting CalculatorPlan a daily fasting schedule. Pick a pattern such as 16:8 and the time your last meal ends to see when the fast ends and when your eating window closes.
- Pregnancy Weight Gain CalculatorSee the 2009 IOM recommended weight gain range for your pre-pregnancy BMI and how your gain so far compares at your current week.
- Race Time Predictor CalculatorUse a recent race time to predict your finish time at another distance, with the Riegel formula and a table of common races.
- Running Splits CalculatorBuild a table of split times per kilometer or mile for a target finish time, with even or negative-split pacing.
- Skinfold Body Fat CalculatorEstimate your body fat percentage from caliper skinfold readings, using the Jackson–Pollock 3-site or 7-site equations and the Siri conversion.
- Sleep Debt CalculatorAdd up a week of nightly sleep against your target to see your accumulated sleep debt and average hours per night.
- Standard Drink CalculatorCount the standard drinks or alcohol units in a drink from its volume and ABV. Use US, UK, Australian or custom definitions.
- Steps to Distance CalculatorConvert a step count to miles or kilometers, or a distance to steps, using your step length or an estimate from height.
- VO2 Max CalculatorEstimate your VO2 max, a measure of aerobic fitness, from a 12-minute run, a 1.5-mile run time, or your maximum and resting heart rates.
- Waist-to-Height Ratio CalculatorDivide your waist measurement by your height, and see how the result compares with the widely used 0.5 screening guideline.
- Waist-to-Hip Ratio CalculatorDivide your waist measurement by your hip measurement and compare the ratio with the WHO screening cutoffs for men and women.
- Weight Loss Percentage CalculatorExpress the weight you have lost as a percentage of your starting weight, with optional progress toward a goal weight.