TDEE Calculator

Total Daily Energy Expenditure (TDEE) is an estimate of how many calories your body uses in a full day, counting everything from breathing and digestion to walking around and formal exercise. It's built on top of a smaller number called your Basal Metabolic Rate (BMR) — the energy your body would burn just to keep itself alive if you stayed in bed all day, doing nothing but existing. TDEE is always larger than BMR because it adds the calories spent on daily movement, digesting food, and any deliberate exercise on top of that baseline.

This calculator estimates BMR using the Mifflin-St Jeor equation: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 for men, or −161 for women. Mifflin-St Jeor was published in 1990 and has since become the equation most widely recommended by dietitians and clinical nutrition guidelines, generally seen as tracking modern body compositions more closely than the older Harris-Benedict equation from 1919, which tends to overestimate calorie needs for many people today.

To go from BMR to TDEE, the calculator multiplies your basal rate by an activity factor: 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderately active, 1.725 for active, and 1.9 for very active. These multipliers are standard reference values, not measurements of your personal metabolism — they're meant to approximate how much extra energy a typical week of movement at each level adds on top of BMR.

The activity level you pick is, by far, the biggest source of error in this whole calculation. Most people tend to overestimate how active they really are — a couple of gym sessions a week combined with a mostly sedentary desk job usually lands closer to 'lightly active' than 'moderately active,' and few people outside of manual labor or serious athletic training genuinely qualify as 'very active.' If your weight isn't changing the way this calculator predicts, the activity level is usually the first place to reconsider, not the formula itself.

Even a well-chosen formula has real limits. Mifflin-St Jeor doesn't know your body composition — two people with the same weight, height, age, and sex can have very different BMRs if one carries noticeably more muscle than the other, since muscle tissue burns more energy at rest than fat tissue. Individual metabolisms also vary for reasons no formula captures, including genetics, hormone levels, and health conditions. Treat the number this calculator gives you as a reasonable starting estimate to test and adjust over a few weeks, not a measured fact about your body.

For weight change, this calculator applies the common rule that roughly 500 kcal/day of sustained deficit or surplus corresponds to about 0.5 kg of weight change per week; the 'mild loss' figure uses a smaller 250 kcal/day gap for a slower, easier-to-sustain pace. It's worth resisting the urge to cut calories more aggressively than this. Steep deficits are hard to sustain, tend to cost you muscle along with fat, and can leave you fatigued or preoccupied with food. For most adults, daily intake shouldn't drop below roughly 1,200 kcal for women or 1,500 kcal for men without guidance from a doctor or registered dietitian, since going lower increases the risk of nutrient shortfalls and other health problems.

This calculator is an educational estimate, not a medical or nutritional prescription, and it isn't intended to set a fixed target weight or promote restrictive eating. If you have a history of disordered eating, a medical condition, or specific fitness goals, a doctor or registered dietitian can tailor recommendations far more precisely than any formula, using your actual body composition and health history rather than five general inputs.