What Is TDEE and How to Calculate It

TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns over a 24-hour period, accounting for all your activity — from breathing while you sleep to running a marathon. Knowing your TDEE is the essential first step for any nutritional goal, whether that's losing fat, gaining muscle, or simply maintaining your current weight.

The 4 components of TDEE

TDEE is not an arbitrary number — it is the sum of four well-defined physiological factors.

• BMR (Basal Metabolic Rate): calories burned at complete rest, just to keep organs functioning. It represents 60–70% of total TDEE in sedentary individuals.^[1]
• TEF (Thermic Effect of Food): the energy your digestive system uses to process food. Roughly 10% of TDEE. Digesting protein costs 20–30% of its calories, while fat costs only 0–3%.^[2]
• NEAT (Non-Exercise Activity Thermogenesis): all spontaneous movement throughout the day — walking to work, fidgeting, changing posture. The most variable component: 200–900 kcal/day depending on lifestyle.^[3]
• EAT (Exercise Activity Thermogenesis): formal planned exercise (gym, running, cycling). Often overestimated: a 1-hour moderate strength session burns roughly 250–350 kcal.

The most accurate formula: Mifflin-St Jeor

Several equations estimate BMR. The most validated for the general adult population is Mifflin-St Jeor (1990), which in a 2005 meta-analysis showed a mean error of 8.8%, versus 11.5% for the revised Harris-Benedict equation.^[1]

• Men: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5
• Women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161

Multiply BMR by your activity factor:

Activity level	Description	Multiplier
Sedentary	Desk job, no exercise	× 1.2
Lightly active	1–3 days/week of light exercise	× 1.375
Moderately active	3–5 days/week of exercise	× 1.55
Very active	6–7 days/week of hard exercise	× 1.725
Extra active	Twice-daily training or physical job	× 1.9

Using TDEE to reach your goals

• Maintenance: eat exactly at TDEE. Weight stabilises long-term.
• Fat loss: create a deficit of 300–500 kcal/day. This yields ~0.3–0.5 kg of fat loss per week without compromising muscle.^[4]
• Muscle gain: add a surplus of 200–300 kcal/day. A larger surplus adds fat without accelerating muscle growth.

The most common mistake: confusing TDEE with BMR

Many apps display BMR as the daily calorie target. Eating at BMR level means an extreme deficit (40–50% below maintenance for an active person), causing muscle loss, metabolic slowdown, and rebound weight gain. Always use full TDEE as your baseline.

How accurate is a calculated TDEE?

Predictive equations have a mean error of 8–15%.^[1] For a calculated TDEE of 2,400 kcal, the true value could be anywhere between 2,040 and 2,760 kcal. Treat the first calculation as a starting point and adjust ±100 kcal every 2–3 weeks based on actual weight trends.

If you'd like to skip the manual calculation, our free TDEE calculator gives you your personalised number in seconds.

Scientific references

1. Frankenfield D et al. "Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults." J Am Diet Assoc. 2005;105(5):775-789.
2. Westerterp KR. "Diet induced thermogenesis." Nutr Metab (Lond). 2004;1(1):5.
3. Levine JA. "Non-exercise activity thermogenesis (NEAT)." Best Pract Res Clin Endocrinol Metab. 2002;16(4):679-702.
4. Hall KD et al. "Quantification of the effect of energy imbalance on bodyweight." Lancet. 2011;378(9793):826-837.