Macro & Calorie Calculator

How the Macro & Calorie Calculator Works

This calculator uses the Mifflin-St Jeor equation, widely considered the most accurate formula for estimating Basal Metabolic Rate (BMR) in healthy adults. Your BMR represents the number of calories your body burns at complete rest just to keep you alive: breathing, circulating blood, and maintaining organ function.

From your BMR, the calculator applies an activity multiplier based on your weekly exercise habits to estimate your Total Daily Energy Expenditure (TDEE). This is the total number of calories you burn in an average day, including all physical activity.

Depending on your goal, the calculator adjusts your TDEE to produce a daily calorie target. For fat loss, it creates a moderate 500-calorie deficit. For muscle gain, it adds 300 calories above maintenance. These adjustments are conservative and sustainable, avoiding the extreme deficits that lead to muscle loss and metabolic slowdown.

Understanding Your Macro Split

Calories alone don't tell the full story. The ratio of protein, carbohydrates, and fat you eat affects body composition, energy levels, recovery, and satiety. This calculator provides a recommended macro split based on your goal:

• Fat loss: Higher protein (40%) to preserve muscle mass during a deficit, moderate carbs (35%), and lower fat (25%).
• Maintenance: A balanced split of 30% protein, 40% carbs, and 30% fat, suitable for general health and stable energy.
• Muscle gain: Moderate protein (30%), higher carbs (45%) to fuel workouts and recovery, and 25% fat.

The per-meal breakdown divides your daily targets across three meals, making it easy to plan what goes on each plate. If you eat more or fewer meals, you can adjust the portions proportionally.

Why Accurate Calorie Tracking Matters

Research consistently shows that people underestimate their calorie intake by 30 to 50 percent. Even nutrition professionals struggle with this. Studies from the New England Journal of Medicine found that dietitians underreported their own intake by an average of 223 calories per day.

Knowing your target is the first step. The second step is actually hitting it consistently. Bento Bunny makes this easy: snap a photo of your meal and get instant calorie and macro breakdowns without manual logging, database searching, or guesswork.