BMR (Basal Metabolic Rate) describes energy used to support basic physiological functions under specific resting conditions. An online calculator cannot replace a controlled metabolic measurement, so this page compares three common equations, averages the available resting-energy estimates, and applies activity factors to derive TDEE (Total Daily Energy Expenditure).
The page shows Revised Harris–Benedict, Mifflin–St Jeor, optional Katch–McArdle, the available-formula average, and TDEE across five activity levels from sedentary to very active. It does not calculate a weight-loss or weight-gain target, read food logs, or model illness, medication, training cycles, or laboratory measurements.
The controls start at age 18, so this is intended as an adult planning reference. Do not rely on it alone for children or teens, pregnancy or breastfeeding, chronic illness, medication that affects appetite or metabolism, eating disorders, or unexplained weight change.
Revised Harris–Benedict and Mifflin–St Jeor use separate male and female coefficient sets, so the selection changes those outputs. It is a formula parameter, not a complete description of sex-related physiology, gender identity, or health status.
BMR describes energy used for basic physiological functions under specific resting conditions; this page estimates it with population equations rather than measuring it in a laboratory or prescribing daily intake.
Revised Harris–Benedict, Mifflin–St Jeor, and optional Katch–McArdle use different assumptions. The page averages the available outputs for comparison, but that average is not guaranteed to be the most accurate.
No. The first two equations work without it. Entering body fat adds Katch–McArdle, but body-fat measurement error directly affects the lean-mass estimate.
BMR is a resting-energy reference; TDEE multiplies the available-formula average by a 1.2–1.9 activity factor and is usually more useful for planning, subject to real-world trend calibration.
Estimate BMR with Revised Harris–Benedict and Mifflin–St Jeor, optionally Katch–McArdle, then compare the formula average and activity-based TDEE; an adult planning estimate, not a metabolic test.