A fictional resting-energy example
For the male source category at age 30 years, 80 kg and 180 cm, the simplified equation gives:
10 × 80 + 6.25 × 180 − 5 × 30 + 5 = 1,780 kcal/day.
For the same fictional measurements, the female source category uses −161 in place of +5 and gives 1,614 kcal/day. These are examples of the two equations, not a recommended intake or a comparison of individuals.
The source equation and rounding
Mifflin and colleagues' 1990 primary research record publishes a simplified resting-energy equation. This tool uses weight in kilograms, height in centimetres and age in whole years:
- Male source category: 10 × weight + 6.25 × height − 5 × age + 5.
- Female source category: 10 × weight + 6.25 × height − 5 × age − 161.
The source study developed its equations in healthy adults. That does not establish their accuracy or suitability for every visitor. FuelForm's source check used the primary-record abstract; it does not claim a new full-paper or clinical review.
The tool keeps unrounded converted measurements for its arithmetic and rounds the final estimate once to a whole kcal/day. Displayed unit conversions use four decimal places at most for reading, without replacing the cached original precision until you edit a measurement. A pound is converted using exactly 0.45359237 kg; an inch is exactly 2.54 cm.
Resting energy, basal energy and daily maintenance
The National Academies' energy-expenditure definitions distinguish basal from resting conditions and describe total expenditure as including more than resting energy. The number here is an RMR/REE prediction. It is not measured BMR, daily maintenance, a minimum safe intake or a personal calorie target.
There is no activity factor, automatic calorie subtraction, body-fat formula switch, macro prescription or goal-date calculation. If you want a separate model of daily maintenance, the maintenance-energy comparison explains its own activity assumptions and method. Do not substitute one number for the other.
Product boundaries and uncertainty
FuelForm supports whole ages 20–78, weights 32–318 kg and heights 122–244 cm, including equivalent imperial measurements. These are chosen product limits, not claimed validation ranges. Pregnancy, breastfeeding, eating-disorder care and prescribed nutrition-treatment plans are outside this tool's scope.
The tool withholds a number below the BMI screening threshold of 18.5, using CDC adult screening categories as the basis for that product rule. BMI is not an individual health assessment, and a result above the threshold is not medical clearance.
A source-category choice and precise-looking output cannot account for every difference in physiology or measurement. Use qualified advice to interpret personal needs. The food-diary guide helps keep a record; it does not validate this prediction or determine what you should eat.
Privacy and technical review
Inputs and results stay in this page's memory. FuelForm does not send calculator values to its server, place them in URLs or browser storage, or include them in calculator analytics. Session recording is disabled here. Changing an input or units clears the old result and its guide link; Reset also clears entries. Your browser or device may separately retain autofill, memory or screenshots. The privacy policy describes the wider website.
This page is product education by FuelForm's founder and product owner. Source equations and arithmetic were checked on 25 October 2026. That is a technical check, not clinical review or a personal health assessment.