Metabolic Age Calculator ⌛

Calculation Methods Explained

Metabolic Age is an indicator, not an actual age. It's the age whose *average* population's Basal Metabolic Rate (BMR) matches your own BMR (which is largely determined by your **Lean Body Mass**).

1. Estimating Metabolic BMR (From Lean Mass)

Your BMR is estimated using your Lean Body Mass ($\text{LBM}$), as muscle is the primary metabolic engine. We use a proxy formula similar to Katch-McArdle:

$$ \text{BMR}_{\text{metabolic}} = 370 + (21.6 \times \text{LBM}_{\text{kg}}) $$
            

Where $\text{LBM}_{\text{kg}} = \text{Weight}_{\text{kg}} \times (1 - \text{BF}\%)$.

2. Calculating Metabolic Age (Reverse Mifflin-St Jeor)

We then solve the Mifflin-St Jeor equation for Age, using the $\text{BMR}_{\text{metabolic}}$ as the target BMR. The resulting age is your Metabolic Age:

$$ \text{Age}_{\text{metabolic}} = \frac{(\text{BMR}_{\text{target}} - \text{Constant}) - (10 \times \text{Weight}) - (6.25 \times \text{Height})}{-5} $$
            

Where $\text{Constant} = 5$ for Men, and $\text{Constant} = -161$ for Women.