What is TDEE (Total Daily Energy Expenditure)?

Total Daily Energy Expenditure (TDEE) is an estimation of how many calories you burn per day when exercise is taken into account. It is the total amount of energy you expend in a 24-hour period. Understanding your TDEE is the most important first step in any fitness journey because it tells you your "maintenance calories"—the number of calories you need to consume to maintain your current weight. Once you know this number, you can accurately plan for weight loss, weight gain, or body recomposition by adjusting your calorie intake accordingly.

The Components of TDEE

Your TDEE is made up of several components:

• Basal Metabolic Rate (BMR): This is the energy your body burns at complete rest to perform life-sustaining functions like breathing and circulation. It's the largest component of your TDEE.
• Thermic Effect of Food (TEF): The calories burned during the digestion and processing of food. Protein has the highest thermic effect.
• Exercise Activity Thermogenesis (EAT): The calories you burn during intentional exercise like running, weightlifting, or playing sports.
• Non-Exercise Activity Thermogenesis (NEAT): The energy expended for everything we do that is not sleeping, eating, or sports-like exercise. This includes walking to work, typing, fidgeting, and performing household chores.

Our calculator simplifies this by first calculating your BMR and then multiplying it by an activity multiplier that accounts for EAT and NEAT.

BMR Formulas: Mifflin-St Jeor vs. Katch-McArdle

Our calculator offers two highly regarded formulas for maximum accuracy.

1. The Mifflin-St Jeor Equation (Default)

This is the modern standard for calculating BMR based on your weight, height, age, and gender. It is considered the most accurate for the general population.

BMR (Men) = 10W + 6.25H - 5A + 5

BMR (Women) = 10W + 6.25H - 5A - 161

(W = weight in kg, H = height in cm, A = age in years)

2. The Katch-McArdle Formula (Advanced)

This formula is considered more accurate if you know your body fat percentage. It calculates your Resting Metabolic Rate (RMR) based on your Lean Body Mass (LBM), which is your total weight minus your fat mass. This is particularly useful for individuals who are very athletic or have a body composition that differs significantly from the average.

BMR = 370 + (21.6 × Lean Body Mass in kg)

Using Your TDEE to Achieve Your Goals

Once your TDEE (maintenance calories) is known, setting up your diet is simple math:

• For Weight Loss: Create a calorie deficit. A deficit of 500 calories per day from your TDEE will result in approximately 0.5 kg of weight loss per week. A smaller deficit of 250 calories will result in about 0.25 kg of loss per week, which can be more sustainable.
• For Weight Gain: Create a calorie surplus. A surplus of 500 calories per day above your TDEE will result in approximately 0.5 kg of weight gain per week. To ensure this gain is primarily muscle, it must be combined with a progressive strength training program.

Our calculator provides these targets for you automatically, taking the guesswork out of your planning.

Frequently Asked Questions (FAQs)

1. Which formula is more accurate for me?

If you do not know your body fat percentage, the Mifflin-St Jeor formula is the best choice. If you have an accurate body fat percentage measurement (from a DEXA scan or other reliable method), the Katch-McArdle formula will likely provide a more precise BMR estimate.

2. How do I accurately choose my activity level?

Be honest about your daily routine. If you have a desk job and go to the gym 3-4 times a week for an hour, you are likely "Moderately Active." If you have a physically demanding job (like a construction worker or farmer) and also exercise, you are likely "Very" or "Extra Active." Most office workers who do some light activity fall into the "Lightly Active" category.

3. Why do my calorie needs change as I lose or gain weight?

As your body weight changes, your BMR also changes. A lighter body requires fewer calories to sustain itself. That's why it's important to recalculate your TDEE every 4-5 kg of weight change to ensure your calorie targets remain accurate for your new body weight.