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Fitness & Health Calculators

Understand the numbers behind your well-being. Every tool is free, with transparent formulas and worked examples.

Calculate adult body mass index with US or metric measurements.

Estimate resting energy needs with the Mifflin–St Jeor equation.

Estimate daily maintenance calories from resting needs and activity.

Convert your chosen calorie target and macro percentages into daily grams.

Explore a historical circumference-based estimate with US or metric measurements.

Solve for pace, elapsed time or distance in kilometers or miles.

Estimate gross and above-rest activity energy from a clearly entered MET value.

Compare Epley and Brzycki predictions from a completed set of up to 10 repetitions.

Estimate a due date from the last period, conception or embryo transfer, with gestational age at a reference date.

Explore approximate cycle dates and a calendar fertile window for an entered regular cycle length.

Explore adult age-estimated maximum heart rate and percentage-of-maximum intensity bands.

Extrapolate an equivalent race finish time from a completed performance using the Riegel equation.