What BMR represents
Basal metabolic rate is the energy required to support essential functions at rest, including circulation, breathing, temperature regulation, and cellular activity. A laboratory can measure resting energy under controlled conditions; this calculator predicts it from weight, height, age, and sex.
Female equation: 10 × kg + 6.25 × cm − 5 × age − 161
BMR is not maintenance calories
Even on a quiet day, you stand, walk, eat, digest food, and perform daily tasks. Those activities raise total daily energy expenditure above BMR. That is why the result also shows two TDEE examples rather than presenting resting energy as an eating target.
Example
If BMR is estimated at 1,650 calories, a sedentary TDEE example is about 1,980 calories while a moderate-activity example is about 2,558. The same resting estimate can therefore lead to very different maintenance needs.
Use the daily calorie calculator when the goal is maintenance, fat loss, or gain.
Why actual resting energy may differ
Muscle mass, genetics, hormones, illness, medication, prolonged dieting, and measurement conditions can all affect resting energy. Formulas are useful because direct testing is not practical for most people, but the result should still be treated as an estimate.
Using the result responsibly
Do not automatically try to eat below BMR. BMR is not a recommended calorie floor and does not account for your full medical or nutrition needs. A registered dietitian or clinician can help when weight change is unexplained, intake is very low, or a health condition affects metabolism.
Implementation evidence
How this calculator is checked
The published Mifflin–St Jeor equation with full precision retained until display rounding.
Expected: 1,649 kcal/day
Expected: 1,483 kcal/day
Expected: Result blocked
These reference cases are exercised during the automated build. They verify arithmetic and input handling; they do not validate the estimate for an individual person. Read the full testing policy.
Frequently asked questions
Is BMR the number of calories I should eat?
Usually not. BMR estimates resting energy. Most adults need additional energy for normal movement and digestion.
Is BMR the same as metabolism?
BMR is one large part of metabolism, but total daily metabolism also includes movement, exercise, and the energy used to digest food.
Can exercise increase BMR?
Exercise burns energy directly and may influence body composition over time. Building muscle can raise resting needs, but the change is usually more modest than social-media claims suggest.
When should I recalculate?
Recalculate after a meaningful change in body weight or when several years, a major lifestyle change, or a major body-composition change makes the original inputs outdated.
Sources
References and further reading
- Mifflin MD et al. — A new predictive equation for resting energy expenditure
- National Institute of Diabetes and Digestive and Kidney Diseases — Body Weight Planner
Method and sources reviewed: July 23, 2026