BMR Calculator
Calories burned at complete rest (Mifflin-St Jeor equation).
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About this calculator
BMR powers breathing, circulation and cell repair while you sleep flat on your back. It's the floor of your energy budget — everything you do stacks on top via activity multipliers.
Mifflin-St Jeor outperformed Harris-Benedict against measured calorimetry in validation trials and remains the dietetic standard today.
Formula
Mifflin-St Jeor: BMR = 10W + 6.25H − 5A + (males: +5 | females: −161)
Health metrics are informational estimates and are not a medical diagnosis.
Frequently Asked Questions
Why does BMR fall with age?
Lean mass declines roughly 3–8% per decade after 30 unless resisted. Preserving muscle keeps BMR higher.
Should I eat below my BMR?
Not deliberately for extended periods — aggressive deficits below resting needs risk nutrient shortfalls, hormonal disruption and lean-mass loss.