BMR & TDEE explained

Your BMR (basal metabolic rate) is the energy your body burns at complete rest. Your TDEE (total daily energy expenditure) is BMR plus everything else you do — moving, digesting, training. TDEE is your maintenance calories.

Estimating BMR

METRI supports three established formulas:

• Harris–Benedict — the classic default.
• Mifflin–St Jeor — often more accurate for modern populations.
• Katch–McArdle — uses lean body mass, best if you know your body fat %.

For example, Mifflin–St Jeor:

BMR = 10 × kg + 6.25 × cm − 5 × age + s
  s = +5 (male) or −161 (female)

From BMR to TDEE

Multiply BMR by an activity factor:

Using the number

• Eat at TDEE to maintain.
• Subtract ~300–500 kcal to lose fat.
• Add ~200–300 kcal to gain lean mass.

Then feed your target into the macro calculator to split it into protein, carbs and fat.