TDEE Calculator — Free 2026

Understanding TDEE and Why It Matters

Total Daily Energy Expenditure, commonly abbreviated as TDEE, represents the total number of calories your body burns over the course of a full day. It encompasses every calorie used — from the energy required to keep your heart beating and lungs breathing while you sleep (your Basal Metabolic Rate, or BMR), to the calories burned during exercise, digesting food, and all the unconscious movements you make throughout the day like fidgeting, standing, and walking around the house. Understanding your TDEE is the foundation of any evidence-based approach to weight management, whether your goal is fat loss, muscle gain, or simply maintaining your current weight.

The reason TDEE matters so much is rooted in the first law of thermodynamics as applied to human metabolism: your body weight changes based on the balance between calories consumed and calories expended. If you consistently eat more calories than your TDEE, the excess energy is stored (primarily as body fat), and you gain weight. If you eat fewer calories than your TDEE, your body draws on its energy reserves, and you lose weight. If intake equals expenditure, your weight stays stable. While the reality of human metabolism involves many nuances — hormones, gut microbiome, sleep quality, stress levels, and individual genetics all play roles — the calorie balance equation remains the most reliable framework for predicting body weight changes over time.

The Mifflin-St Jeor Equation

This calculator uses the Mifflin-St Jeor equation, which was published in 1990 and is considered the most accurate predictive equation for estimating BMR in healthy adults by the Academy of Nutrition and Dietetics. The formulas are:

Men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) + 5
Women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) - 161

BMR represents the calories your body needs at complete rest — the energy cost of simply being alive. It accounts for roughly 60-75% of total daily energy expenditure in most people. The remaining calories come from physical activity (15-30%) and the thermic effect of food (about 10% of calorie intake).

Activity Multipliers Explained

To convert BMR into TDEE, we multiply by an activity factor that accounts for your overall daily movement. The sedentary multiplier (1.2) applies to people who work desk jobs and get minimal exercise. Lightly active (1.375) covers light walking or exercise 1-3 times per week. Moderately active (1.55) suits people who exercise at moderate intensity 3-5 days per week. Very active (1.725) is appropriate for people who train hard nearly every day. Extra active (1.9) is reserved for elite athletes, manual labourers, or those who exercise intensely twice daily. One of the most common mistakes people make is overestimating their activity level — most office workers, even those who exercise regularly, fall into the lightly active or moderately active category.

Macronutrient Breakdown

Beyond total calories, the composition of your diet matters. This calculator provides a recommended macronutrient split based on widely accepted sports nutrition guidelines. Protein is set at 2 grams per kilogram of body weight, which supports muscle protein synthesis and helps preserve lean mass during a calorie deficit. Fat is set at 25% of target calories, ensuring adequate hormone production and absorption of fat-soluble vitamins. The remaining calories are allocated to carbohydrates, which fuel high-intensity exercise and brain function.

These macronutrient targets are starting points. Endurance athletes may need more carbohydrates, while those following a ketogenic approach will shift calories from carbs to fat. If you want to track your body composition more precisely, our BMI calculator and body fat calculator can provide additional context.

Setting Realistic Goals

A calorie deficit of 500 calories per day produces approximately 0.5 kg (1 pound) of weight loss per week, while a 1,000-calorie deficit doubles that rate. However, aggressive deficits can lead to muscle loss, metabolic adaptation, nutrient deficiencies, and difficulty sustaining the diet long term. Most nutrition professionals recommend a moderate deficit of 300-500 calories below TDEE for sustainable fat loss. For muscle gain, a surplus of 200-500 calories is typically sufficient — larger surpluses tend to increase fat gain without proportionally increasing muscle growth.

Limitations and Individual Variation

All TDEE calculators provide estimates, not exact measurements. Individual variation in metabolic rate can differ by 200-300 calories from predicted values due to differences in genetics, body composition, thyroid function, and other factors. The most reliable way to determine your true TDEE is to track your calorie intake and body weight consistently over 2-4 weeks and adjust based on the trend. If your weight is stable, your average intake equals your TDEE. If you are losing or gaining, you can calculate the discrepancy and adjust accordingly.