How to Calculate Daily Calories (TDEE and Basal Metabolism)

For anyone who wants to change their body composition — whether to lose weight, gain muscle mass or simply maintain their current weight in a healthy way — the fundamental rule is based on the thermodynamics of energy balance: consuming less energy than you expend generates weight loss, and consuming more generates weight gain.

However, to apply this rule successfully, the first step is to know how much energy your body consumes every day. This metric is known as TDEE (Total Daily Energy Expenditure).

In this article, we explain what makes up energy expenditure and how you can use our Daily Calorie Calculator to plan your diet in a scientific way.

1. What makes up your Daily Caloric Expenditure?

TDEE is the sum of four main energy-burning components in the body:

1. Basal Metabolic Rate (BMR): The energy that your body spends at absolute rest just to maintain vital functions (breathing, heartbeat, temperature regulation). It represents 60% to 75% of daily spending.
2. Thermal Effect of Food (ETA): The energy used to chew, digest, absorb and metabolize the food ingested (about 10% of the daily total). Proteins take more energy to be digested than carbohydrates and fats.
3. Physical Activity Thermogenesis (EAT): Calories burned during planned physical exercises (weight training, running, swimming).
4. Non-Exercise Activity Thermogenesis (NEAT): The calories you burn in everyday non-exercise activities (walking to the bus stop, cleaning the house, climbing stairs, standing). Increasing NEAT is one of the most effective strategies for losing weight.

2. The Mifflin-St Jeor Formula for BMR

The Mifflin-St Jeor equation is today considered the most accurate mathematical formula and recommended by nutritionists to estimate the Basal Metabolic Rate in adults. The formulas are:

• For Men: $\text{TMB} = 10 \times \text{Peso (kg)} + 6,25 \times \text{Altura (cm)} - 5 \times \text{Idade (anos)} + 5$
• For Women: $\text{TMB} = 10 \times \text{Peso (kg)} + 6,25 \times \text{Altura (cm)} - 5 \times \text{Idade (anos)} - 161$

After calculating the BMR, the value is multiplied by the person's Activity Factor (sedentary, slightly active, moderately active, very active) to find the final TDEE.

3. How to Adjust Calories to Your Goal

With your TDEE value in hand, adjust your daily caloric intake:

• To Lose Weight (Caloric Deficit): Reduce 300 to 500 calories from your daily TDEE. This generates a healthy and sustainable weight loss of approximately 0.5 kg per week, preserving muscle mass.
• To Gain Mass (Caloric Surplus): Add 200 to 300 calories to your daily TDEE. Combine this with consistent strength training (bodybuilding) to ensure that the gain is in muscle tissue, and not just fat.
• To Maintain Weight: Consume exactly the amount equivalent to your daily TDEE.

Calculate Your Calories Now

Doing these calculations manually requires complex formulas and multiple adjustment factors.

We created a simple, free tool based on the Mifflin-St Jeor equation to calculate your daily expenditure and provide calorie targets based on your goal. Click here to access our Daily Calorie Calculator (TDEE)!