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 daily calorie needs by multiplying estimated BMR by an activity factor.
Estimate total daily energy expenditure (TDEE) from age, sex, height, weight and activity level using the Mifflin–St Jeor BMR equation.
Estimate basal metabolic rate using the Mifflin–St Jeor equation.
Estimate adult body-fat percentage from body measurements using the U.S. Navy circumference method.
Compare several common adult ideal-body-weight formulas based on sex and height.
Calculate average running pace and speed from distance and elapsed time.
Estimate one-repetition maximum (1RM) from a lifted weight and repetition count using common strength formulas.
Convert a daily calorie target and macro percentages into grams of protein, carbohydrates and fat.
Create a simple daily hydration planning estimate from body weight, a chosen ounces-per-pound factor and optional exercise fluid.
12 focused guides and worked examples for this calculator cluster.
Learn the standard adult BMI ranges and how to interpret underweight, healthy weight, overweight and obesity categories.
Read guide →Health & Body MetricsCalculate adult BMI from weight in kilograms and height in meters using the metric formula.
Read guide →Health & Body MetricsCalculate adult BMI from weight in pounds and height in inches using the standard U.S. formula.
Read guide →Health & Body MetricsLearn the difference between basal metabolic rate and an activity-adjusted daily calorie estimate. See formulas and worked examples.
Read guide →Health & Body MetricsCompare body-fat percentage and body mass index and learn what each estimate can and cannot tell you.
Read guide →Health & Body MetricsLearn how healthy-weight estimates are commonly derived from height and why different formulas can produce different answers.
Read guide →Health & Body MetricsLearn the adult BMI formula using height and weight and why BMI is a screening estimate rather than a diagnosis.
Read guide →Health & Body MetricsLearn a simple age-based method for estimating maximum heart rate and percentage-based exercise zones.
Read guide →Health & Body MetricsEstimate maximum heart rate from age using a common age-based formula and understand its limitations.
Read guide →Health & Body MetricsSee example maximum-heart-rate estimates by age and learn how the 220 minus age rule changes over time.
Read guide →Health & Body MetricsLearn a simple body-weight-based way to estimate daily protein intake and how calorie targets and goals can affect the number.
Read guide →Health & Body MetricsLearn a simple way to estimate daily water intake from body weight and why activity level and climate can change the number.
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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