Health & Body Composition
Metabolic Age Calculator
Metabolic age compares your resting calorie burn with the average for your age group. Burn more than your peers and your metabolism reads younger.
Metabolic age compares your basal metabolic rate with the average BMR for your chronological age group. A metabolic age lower than your real age suggests a higher metabolic rate than typical peers. Results are screening estimates, not diagnoses — confirm with a clinician before acting on them.
Based on Mifflin-St Jeor BMR.
Younger metabolic age = higher burn.
Muscle mass raises BMR and lowers metabolic age.
Calculate Your Metabolic Age
Your Metabolic Age
What Is Metabolic Age?
Metabolic age compares your basal metabolic rate (BMR), the calories you burn at complete rest, with the population average for your chronological age and sex.
If you burn more than average for your age, your metabolism 'reads' younger. Because muscle mass is the biggest modifiable driver of BMR, strength training is the most reliable way to improve metabolic age.
How It Is Calculated
Mifflin-St Jeor BMR = 10W + 6.25H − 5A + 5 (men) or −161 (women)
Metabolic age = age band whose average BMR matches yours
Example: Example: a 40-year-old man burning 1,800 kcal/day at rest reads ≈ 34 metabolic years
Average BMR by age band (Mifflin-St Jeor, kcal/day)
| Age band | Men | Women |
|---|---|---|
| 20–29 | 1,560 | 1,370 |
| 30–39 | 1,500 | 1,330 |
| 40–49 | 1,440 | 1,290 |
| 50–59 | 1,380 | 1,240 |
| 60–69 | 1,320 | 1,190 |
| 70+ | 1,250 | 1,140 |
Limitations
- BMR formulas are estimates; indirect calorimetry is the gold standard.
- Age-band averages are approximations of population data.
- Muscle mass, thyroid function, and illness all move BMR.
- Metabolic age is a fitness concept, not a medical diagnosis.
Sources & Review
References used for this calculator’s formulas and thresholds:
Metabolic Age FAQ
What is a good metabolic age?
A metabolic age below your real age, it means your resting calorie burn is higher than the average for your age group.
How can I lower my metabolic age?
Build muscle mass through strength training, stay active, eat enough protein, and sleep well. BMR tracks lean mass closely.
Does metabolic age mean my health age?
No, it only reflects resting energy burn. Health age considers blood pressure, lipids, and other markers; metabolic age is a narrower fitness concept.
Why is my BMR lower than my friends'?
BMR scales with body size and lean mass, and declines with age. Two people of the same weight can differ because muscle burns more than fat.
Important disclaimer: Results are educational estimates, not a substitute for professional medical advice. Discuss your numbers with a clinician before acting on them.