BMI, BMR, calorie needs, body measurements and heart-rate estimates for general reference. Use the calculators for your own numbers and the guides for formulas, examples and common questions.
Use the tool that matches the exact problem you need to solve.
Estimate body mass index from height and weight using the standard adult BMI formula.
Estimate basal metabolic rate using the Mifflin–St Jeor equation.
Estimate daily calorie needs by multiplying estimated BMR by an activity factor.
Estimate body surface area using the Mosteller formula.
Calculate waist-to-height ratio using waist circumference and height in the same units.
Estimate exercise heart-rate zones from age using a simple percentage of estimated maximum heart rate.
Three long-tail answers that explain formulas and common scenarios behind this calculator cluster.
Learn the adult BMI formula using height and weight and why BMI is a screening estimate rather than a diagnosis.
Read guide →Health & Body MetricsLearn the difference between basal metabolic rate and an activity-adjusted daily calorie estimate.
Read guide →Health & Body MetricsLearn a simple age-based method for estimating maximum heart rate and percentage-based exercise zones.
Read guide →BMI, BMR, calorie needs, body measurements and heart-rate estimates for general reference. The pages in this cluster are intentionally connected: calculator pages handle the arithmetic, while the guides answer informational searches, show worked examples and explain how to interpret the result.
Use the examples as reference points, then open a calculator and substitute your own values. For decisions involving contracts, taxes, health, payroll rules, construction requirements or other high-stakes details, verify the real-world assumptions with an appropriate authoritative source.
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