Estimate adult basal metabolic rate with Mifflin–St Jeor, revised Harris–Benedict, or Katch–McArdle, plus a clearly labeled activity-multiplier TDEE scenario.
A quick decision brief for this specific tool
Adult age 18–100, weight and height within displayed bounds, one published sex equation constant, a BMR formula, required body-fat percentage for Katch–McArdle, and one broad activity multiplier
Selected adult BMR estimate, equation comparison where inputs permit, and one activity-multiplier TDEE scenario
Mifflin–St Jeor, revised Harris–Benedict, or Katch–McArdle after strict validation; TDEE scenario = selected BMR × selected activity factor
Choose your path
Estimate adult resting energy with a deliberately selected published equation and separate it from a broad activity-multiplier scenario or dietary prescription.
Compare a population BMR estimate without receiving an invented diet plan.
Enter adult measurements, choose Mifflin–St Jeor, and inspect BMR plus the separately labeled activity scenario.
Understands neither value is measured metabolism, diagnosis, or a safe calorie target.
Use Katch–McArdle only when a body-fat estimate is available.
Select Katch–McArdle and provide a body-fat value within the supported range.
Missing or invalid body fat fails visibly instead of silently switching equations.
Know whether the tool applies during youth, pregnancy, or breastfeeding.
Review the adult-only scope before relying on an estimate.
Uses individualized clinical guidance rather than applying this population equation outside scope.
Tools you might need next
Compare adult BMR equations and a selected activity-multiplier TDEE scenario without generating calorie, macro, or meal prescriptions.
Convert a user-selected energy total and carbohydrate, protein, and fat percentages into calories and grams with adult AMDR context.
Calculate adult BMI from metric or imperial height and weight. See CDC screening categories, formula steps, and limitations without treating BMI as a diagnosis.
A commonly used adult resting-energy equation based on weight, height, age, and a published sex-specific constant. Individual error can be meaningful compared with indirect calorimetry.
Men: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + 5 | Women: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age − 161The selected activity factor produces a planning scenario. It does not measure exercise, digestion, non-exercise movement, adaptation, or an individual's true daily expenditure.
TDEE = BMR × Activity Factor (1.2 sedentary to 1.9 very active)Katch–McArdle requires a body-fat percentage to estimate lean mass. The calculator rejects missing or out-of-range body-fat input instead of silently substituting another formula.
Lean mass = weight × (1 − body-fat fraction); BMR = 370 + 21.6 × lean mass(kg)Updated: August 2026
Calculating resting metabolic rate for a moderately active 35-year-old man planning a nutrition program.
→ BMR: ~1,780 kcal/day
An adult compares the resting estimate with a selected activity-multiplier scenario before seeking individualized nutrition guidance.
→ BMR: ~1,380 kcal/day
A gym member records consistent inputs to compare population-equation estimates over time without treating a calculated change as measured metabolic adaptation.
BMR is a resting estimate. The activity multiplier is also only a scenario; neither output establishes a safe intake target. Use individualized professional guidance for dietary changes.
Equation results change with weight and other inputs, but they do not directly measure adaptation or explain a plateau. Re-enter accurate measurements and interpret trends cautiously.
Estimate resting energy expenditure for adults age 18–100, then view one activity-factor scenario. The result is a population estimate—not measured metabolism, a diagnosis, or a calorie prescription—and this tool is not intended for pregnancy, breastfeeding, or minors.