Free Calculator · Mifflin-St Jeor Formula

How Many Calories Should I Eat?

Enter your details and get your personalized daily calorie target — calculated with the Mifflin-St Jeor formula, the most accurate method used by nutritionists.

The Mifflin-St Jeor Formula

The Mifflin-St Jeor equation is the most accurate formula for calculating BMR (Basal Metabolic Rate). For men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5. For women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. Multiply by your activity factor to get TDEE.

Why your calorie needs change over time

As you lose weight, your BMR decreases — you burn fewer calories at rest. This is why weight loss slows down over time and why your calorie target should be recalculated regularly. Eatrim does this automatically as your weight changes.

Common mistakes when setting calorie targets

The most common mistake is cutting calories too aggressively. Going below 1,200 kcal for women or 1,500 kcal for men triggers metabolic adaptation — your body slows down to conserve energy. Sustainable deficits of 300-500 kcal lead to better long-term results than extreme restriction.

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