About this BMR calculator
This site estimates adult resting energy from published equations and explains the limits of those estimates.
Scope
Mifflin–St Jeor is the primary general-adult estimate. Revised Harris–Benedict is shown as a comparison. Cunningham is available when body-fat percentage is supplied, and Ten Haaf is available as an athlete-specific comparison.
The calculator accepts adults from age 18. Mifflin’s original derivation sample covered ages 19–78, so age 18 and ages above 78 receive a study-range note.
Calculation policy
Equation results stay separate. The site rounds results to whole calories and explains when age, body composition, athlete status, pregnancy, major illness, or recent weight loss can change how the estimate should be read.
Limits
The calculator is for education and general estimation. Clinical feeding decisions, pregnancy and lactation planning, pediatric assessment, and cases that require measured resting expenditure need professional assessment.
Sources
The methodology gives the formulas and calculation rules. The references list the primary papers, systematic reviews, and evidence summaries used for the site.