Fitness & Performance
BMR Calculator
Your basal metabolic rate is the calories your body burns just staying alive, the foundation of every calorie plan.
BMR (basal metabolic rate) is the number of calories your body burns at complete rest to keep vital functions running. The Mifflin-St Jeor equation estimates BMR from weight, height, age, and sex. Use the result as a training benchmark — retest under the same conditions to track progress.
Mifflin-St Jeor is the modern standard.
~60–70% of daily burn is BMR.
Muscle mass raises BMR.
Calculate Your BMR
Your BMR
What Is BMR?
Basal metabolic rate (BMR) is the energy your body spends at complete rest, keeping your heart beating, brain working, and cells repairing. It typically accounts for 60–70% of daily energy use.
This calculator shows the Mifflin-St Jeor equation, the most accurate general formula, alongside the revised Harris-Benedict for comparison.
How It Is Calculated
Mifflin-St Jeor: BMR = 10W + 6.25H − 5A + 5 (men) / −161 (women)
Harris-Benedict (rev): 88.362 + 13.397W + 4.799H − 5.677A (men)
Example: Example: 30-year-old man, 75 kg, 175 cm → BMR ≈ 1,725 kcal/day
What drives BMR
| Factor | Effect |
|---|---|
| Lean body mass | Biggest driver, more muscle = higher BMR |
| Body size | Larger bodies burn more at rest |
| Age | BMR falls ~1–2% per decade after 30 |
| Sex | Men average higher due to more lean mass |
Limitations
- Equations estimate typical values; individual variance is ±10%.
- Illness, thyroid conditions, and medications change real BMR.
- Very muscular or very large bodies are better served by Katch-McArdle (lean-mass) formulas.
Sources & Review
References used for this calculator’s formulas and thresholds:
BMR FAQ
What is a normal BMR?
Typical adult BMR ranges from about 1,200 to 2,000 kcal/day, mostly set by body size and lean mass. There's no single 'normal', it scales with you.
Why does BMR matter for weight loss?
BMR is the floor of your daily burn. Eating too far below it triggers muscle loss and metabolic adaptation, most plans target 10–20% below TDEE, not below BMR.
Can I raise my BMR?
Yes — build muscle, eat adequate protein, sleep well, and stay active. Lean mass is the main lever you control.
Which BMR formula is most accurate?
Mifflin-St Jeor is the modern standard. If you know your body fat percentage, the Katch-McArdle formula is more accurate still.
Important disclaimer: Results are educational estimates, not a substitute for professional advice. Review your numbers with a qualified advisor before acting on them.