Health & fitness calculators

Understand adult BMI and why it cannot diagnose anorexia, assess an eating disorder or establish an underweight target.

Compare the 2026 Army waist-to-height threshold using recorded measurements, or explore the historical 2023 body-fat equation.

Calculate adult BMI or CDC BMI-for-age percentiles for ages 2 to under 20, with the screening limits of each method explained.

Estimate adult resting energy expenditure using the available equations, and convert food energy between kilocalories and kilojoules.

Estimate body-fat percentage using historical circumference equations or the age- and sex-adjusted BMI study model.

Estimate adult daily maintenance calories from body measurements and activity assumptions, with food-energy unit conversion.

Estimate activity calories using METs, selected Compendium activities or a distance-and-speed approximation, with gross and net energy shown.

Explore the adult BMI-based reference weight interval for a height, including the exclusive upper boundary and screening limitations.

Compare historical adult reference-weight equations or use CDC child BMI-for-age references without setting a personal target weight.

Compare lean-mass estimates from entered body fat, Boer, James, Hume or the pediatric Peters method, with equation-specific limits.

Estimate a one-repetition maximum from a submaximal lift using Epley, Brzycki and supported Lombardi comparisons.

Explore adult BMI screening categories from height and weight, with clear limits on what the result can say about individual health.

Calculate pace, speed, time and distance, review cumulative splits, or project a finish from the average pace so far.

Compare estimated maximum heart rates and target ranges, or use the talk test to check exercise intensity.

Explore a rough Widmark blood-alcohol estimate from one drink input or multiple beverages, with major safety limitations made explicit.

Estimate body surface area with eight named equations, age-specific branches and metric or US area units.

Explore body proportions and the 2020 revised FFIT fashion descriptors with their measurement limitations.

Estimate carbohydrate grams from a calorie target and percentage, or explore adult energy-based carbohydrate reference ranges.

Convert a selected share of daily calories into fat grams and compare adult energy-based fat-intake reference ranges.

Estimate eGFR with adult race-free CKD-EPI 2021 or pediatric bedside Schwartz equations, using creatinine and model-specific inputs.

Convert a daily energy target into protein, carbohydrate and fat grams, or explore adult reference ranges from body measurements.

Estimate daily protein grams from body weight and a chosen g/kg target, or compare adult energy-based protein reference ranges.

Estimate total daily energy expenditure by combining an adult resting-energy equation with your selected activity factor.

Estimate a possible fertile window from cycle history and explore menstrual, conception, ultrasound or IVF pregnancy-dating methods.

Estimate a due date from the last period, conception date, IVF transfer or ultrasound dating, using the selected method's inputs.

Estimate ovulation timing and a possible fertile window from cycle length and luteal-phase assumptions, without confirming ovulation.

Project a next-period date from menstrual history and assumed cycle length, with associated cycle estimates and their limitations.

Estimate pregnancy dates from menstrual history, conception, ultrasound, IVF transfer or a known due date, with dating assumptions explained.

Estimate conception timing from a known due date or other pregnancy-dating information, while keeping the uncertainty of dates explicit.

Compare pregnancy weight gain with BMI-specific singleton or twin reference guidance, without prescribing an exact week-by-week target.