BODY & TRAINING / TOOL COLLECTION

Health and fitness calculators with the sources shown.

Body mass index, calorie and protein needs, body fat, heart-rate zones, one-rep max, pace and calories burned, each from published public-health or peer-reviewed formulas.

See the 12 calculators
01 / TOOLS IN THIS COLLECTION12 CALCULATORS

Choose your tool.

01 / TOOLBMI CalculatorBody mass index for adults with CDC categories, and BMI-for-age percentiles for ages 2 to 19.Open calculator 02 / TOOLCalorie CalculatorDaily calorie needs (TDEE) from the NASEM 2023 equations, and targets to lose or gain weight.Open calculator 03 / TOOLBMR CalculatorBasal metabolic rate by Mifflin-St Jeor, Harris-Benedict and Katch-McArdle, side by side.Open calculator 04 / TOOLIdeal Weight CalculatorHealthy weight range for your height from BMI, plus the classic Devine, Robinson, Miller and Hamwi estimates.Open calculator 05 / TOOLBody Fat CalculatorBody fat percentage by the U.S. Navy tape method and from BMI, with fat and lean mass.Open calculator 06 / TOOLLean Body Mass CalculatorLean body mass by the Boer, James and Hume formulas, or from a known body fat percentage.Open calculator 07 / TOOLProtein CalculatorDaily protein in grams by body weight, from the RDA to athletic ranges, split per meal.Open calculator 08 / TOOLMacro CalculatorSplit a calorie target into protein, carbohydrate and fat grams within recommended ranges.Open calculator 09 / TOOLTarget Heart Rate CalculatorMaximum heart rate and exercise zones by age, percent of max or heart-rate reserve.Open calculator 10 / TOOLOne Rep Max CalculatorEstimate your one-rep max from a set, with seven equations and a percentage table.Open calculator 11 / TOOLPace CalculatorRunning or walking pace, time or distance from the other two, with splits and race times.Open calculator 12 / TOOLCalories Burned CalculatorCalories burned by activity, weight and time, from the 2024 Compendium of Physical Activities.Open calculator
02 / HOW TO CHOOSE

Start with
the right question.

Start with the BMI calculator for a CDC screening category (including percentiles for children and teens), then the ideal weight calculator for a healthy range at your height. The BMR and calorie calculators estimate energy needs, and protein and macro turn a calorie target into grams. Body fat and lean body mass use tape measurements or formulas. For training, use target heart rate, one-rep max, pace and calories burned. These tools are informational and do not replace advice from a clinician.

WORKED EXAMPLE

A 5 ft 9 in adult weighing 180 lb has a BMI of 26.6. A 40-year-old has an estimated maximum heart rate of 180 bpm (220 − 40), so moderate exercise is about 90 to 126 bpm.

QUESTIONS / 03SHORT ANSWERS

Common questions.

Is BMI a diagnosis?

No. The CDC describes BMI as a screening measure: it does not measure body fat directly. Talk to a health professional about what a result means for you.

Why do calorie calculators disagree?

Each uses a different equation fitted to different people. Our calorie calculator uses the 2023 National Academies equations and shows their typical error, and the BMR calculator shows three equations side by side.