How this calculation works
This tool uses the simplified Mifflin–St Jeor equation to estimate resting energy expenditure from weight, height, age and the equation’s sex category. Although often called a BMR calculator, it does not measure basal metabolism in a laboratory. The result covers resting needs, not an entire day of movement, exercise and food digestion.
Worked example
This example uses illustrative inputs. Your current result is shown above.
For the male equation at 70 kg, 175 cm and age 30: 10 × 70 + 6.25 × 175 − 5 × 30 + 5 = 1,648.75, displayed as 1,649 kcal/day. With the female equation and the same measurements, the result is 1,482.75, displayed as 1,483 kcal/day.
Assumptions and limits
- This is an adult population-based equation, not an individual metabolic test. Its original research sample was aged 19–78; accepting a wider input range does not establish accuracy at those extremes.
- The two sex-specific offsets reflect the published equation’s categories and do not model every person’s physiology, body composition, hormonal status or medical condition.
- Pregnancy, lactation, growth, illness and major body-composition differences are not modelled. A positive result is not proof that it is a suitable food-intake target.
Questions people ask
Should I eat exactly my BMR result?
No. Resting expenditure excludes much of everyday activity. The number is not a prescribed intake or a safe minimum; a qualified professional can assess individual needs.
How is this different from the TDEE calculator?
TDEE multiplies this resting estimate by an assumed activity factor. That adds another layer of uncertainty rather than measuring energy use.
Why does selecting the other equation change the answer?
The weight, height and age terms stay the same; the published sex-specific offset changes by 166 kcal/day.