BMR Calculator

Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest just to keep you alive: breathing, circulating blood, repairing cells, and running your brain and organs. It does not include digestion, movement, or exercise - it is the floor, not the total. Most people never see this number, even though it is the single most important input for any calorie or macro target that follows.

This calculator uses the Mifflin-St Jeor equation, published in 1990 and still the equation most widely recommended by dietitians and used in clinical practice today, because it consistently outperforms older formulas like Harris-Benedict on modern body-composition data. It takes four inputs - weight, height, age and biological sex - and produces a single estimate in kilocalories per day. There is no faster or more accurate formula-based BMR estimate available without a metabolic cart (indirect calorimetry, the lab-grade gold standard that most people will never have access to).

Knowing your BMR matters for one practical reason: it is the safety floor Mealyno uses to keep weight-loss recommendations healthy. Eating consistently below BMR for extended periods can trigger metabolic adaptation - your body slowing its own energy expenditure to compensate - along with fatigue and a much higher chance of the weight coming back. Every calorie target this app generates, in the product and in the calorie calculator below, is clamped so it never drops below your calculated BMR.

Use this number as a reference point, not a target to eat at. Your Total Daily Energy Expenditure (TDEE) - BMR multiplied by an activity factor - is what you should actually aim to eat around, adjusted up or down depending on whether your goal is to lose, maintain, or gain weight. If you want that next step, the TDEE calculator and calorie calculator below build directly on the BMR figure you get here.