TDEE Calculator

What is TDEE (Total Daily Energy Expenditure)?

Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a 24-hour period, including every biological process and every movement. It is the single most useful number for meal planning, weight management, and macronutrient calculation. TDEE has four components: Basal Metabolic Rate (BMR) accounts for 60–75% of total burn and covers vital functions at rest; Thermic Effect of Food (TEF) is the energy required to digest, absorb, and store nutrients — typically 8–12% of calories eaten, highest for protein (20–30%) and lowest for fat (0–3%); Exercise Activity Thermogenesis (EAT) covers intentional workouts; and Non-Exercise Activity Thermogenesis (NEAT) covers fidgeting, standing, walking between meetings, and other unconscious movement. NEAT varies by up to 2000 kcal/day between individuals of similar size — it is the single biggest source of inter-individual TDEE variation.

How to calculate TDEE

TDEE is calculated in two steps. First, estimate your Basal Metabolic Rate with the Mifflin-St Jeor equation. Second, multiply BMR by an activity factor between 1.2 and 1.9 depending on lifestyle and training volume. For a 30-year-old man with a BMR of 1780 kcal doing three weekly strength sessions (factor 1.55), TDEE is 1780 × 1.55 = 2759 kcal/day. The same person at a sedentary desk job with no training (factor 1.2) would have a TDEE of only 2136 kcal — a 623 kcal difference. Activity multipliers are population averages; individual variation of ±10–20% is common, driven mostly by NEAT. If your weight trend doesn't match your calculated TDEE after 2–3 weeks of consistent tracking, adjust the multiplier down one step. Tracking weight daily and averaging weekly smooths out water-weight noise.

Using TDEE for weight loss, maintenance, and gain

Weight change is governed by the energy balance equation: calories in minus calories out determines whether you lose, maintain, or gain weight. To maintain weight, eat at your TDEE. To lose fat, eat 300–500 kcal below TDEE (a 10–20% deficit), which produces 0.3–0.5 kg/week of loss while preserving muscle, especially when combined with resistance training and protein at 1.6–2.2 g/kg bodyweight (Helms et al., 2014). To gain muscle, eat 200–400 kcal above TDEE with the same protein target — faster gains lead to disproportionate fat accumulation. Deficits larger than 25% of TDEE accelerate lean-mass loss and reduce training performance. The 3500 kcal = 1 pound rule is a useful approximation but breaks down over multi-month timelines due to metabolic adaptation.

Why does TDEE decrease during weight loss?

TDEE decreases during weight loss for three reasons. First, you have less mass to carry, so both BMR and the calorie cost of movement fall proportionally. Second, NEAT drops as the body conserves energy — a 2013 study in the American Journal of Clinical Nutrition found NEAT reductions of 300–500 kcal/day during dieting. Third, adaptive thermogenesis reduces BMR by 5–15% beyond what weight loss alone would predict. A well-documented 2016 Obesity study by Fothergill et al. on contestants from The Biggest Loser found that 6 years after rapid weight loss, their resting metabolic rates were still 500 kcal/day below predicted. Recalculate your TDEE every 5 kg of weight change, and take diet breaks at maintenance every 8–12 weeks to reduce adaptation.

Why muscular people often need more than TDEE suggests

Standard TDEE calculators use weight, height, age, and sex — they cannot see body composition. This matters because muscle tissue consumes roughly 13 kcal per kg per day at rest, versus about 4.5 kcal for fat tissue. Two people at 80 kg can have BMRs 100–200 kcal apart if one has 15 kg more lean mass. The Katch-McArdle formula (BMR = 370 + 21.6 × lean body mass in kg) is more accurate for muscular individuals who know their body fat percentage from a DEXA scan. Additionally, resistance training creates an excess post-exercise oxygen consumption (EPOC) effect that modestly raises calorie burn for 12–48 hours after a hard session. If Mifflin-St Jeor-based TDEE seems to undershoot your actual needs by consistent amounts, try Katch-McArdle.