TDEE Calculator

Total Daily Energy Expenditure is the total number of calories your body uses in 24 hours. It's the sum of your basal metabolic rate (breathing, heart, brain), the thermic effect of food (digestion uses ~10% of intake), and activity (everything from fidgeting to formal exercise). TDEE is the calorie level at which your weight stays the same — eat less to lose, more to gain.

Multiple validation studies (most notably Frankenfield 2005) compared the major BMR equations against measured calorimetry and found Mifflin–St Jeor to be the most accurate for healthy modern adults — within roughly ±10% of true BMR for about 70% of people. Harris–Benedict was derived in 1919 from a sample that does not reflect today's body composition, and tends to overestimate BMR by 5–15%. The American Dietetic Association recommends Mifflin–St Jeor.

Most people overestimate. Use: Sedentary (1.2) — desk job, no formal exercise; Light (1.375) — desk job + 1–3 light workouts/week; Moderate (1.55) — 3–5 hard workouts/week or a moderately active job; Active (1.725) — 6–7 hard workouts/week or a physical job; Very active (1.9) — physical job and daily intense training (construction worker who also lifts).

For most healthy adults, the calculated TDEE is within roughly ±10–15% of true energy expenditure. The largest source of error is the activity multiplier — you may genuinely fall between two levels, or your training week varies. Use the calculator's number as a starting point, eat that level for 2–3 weeks, and adjust by ±100–200 kcal based on what your scale shows.

A deficit of 500 kcal/day typically produces about 1 lb (0.45 kg) of fat loss per week — the rule-of-thumb that 3,500 kcal = 1 lb of body fat. That is sustainable for most people and minimises muscle loss. Larger deficits (>20–25% of TDEE) work short-term but increase risk of muscle loss, fatigue, low mood, and rebound. Mild deficits (250 kcal) are ideal for very lean people, athletes, or anyone with little weight to lose.

Yes — every 5–10 lbs (2.5–5 kg) of weight loss is a good time to recalculate. A lighter body burns fewer calories at rest and during movement, so deficit calories shrink with you. There is also a separate phenomenon called adaptive thermogenesis where BMR drops by an extra 5–15% after sustained dieting, which is why long cuts often require periodic diet breaks.

No. TDEE is your maintenance — the calories that keep your weight stable. Your limit depends on goal: TDEE − 500 for loss, TDEE + 500 for gain, TDEE itself for maintenance. The calculator shows all six options.

Yes — the activity multiplier already includes your typical weekly exercise. You should NOT add exercise calories back on top. If you wear a fitness tracker that shows "calories burned" for each workout, those are estimates of expenditure that get folded into the multiplier we used. Eating extra on workout days is fine if you are bulking, but for fat loss treat TDEE as the daily total.

Wrist-based devices (Apple Watch, Fitbit, Garmin) routinely overestimate calorie burn by 15–40%, especially during weight training. They rely on heart rate and movement to guess energy use, which is noisy. Trust your TDEE calculation and your scale weight over what your watch reports.

Slightly — each pound of muscle burns about 6 kcal/day at rest, vs ~2 kcal for fat. Adding 10 lbs of muscle therefore raises BMR by ~50 kcal/day, less than most people imagine. The bigger reason muscular people burn more is that strength training itself elevates expenditure (and EPOC) for hours afterwards.

Yes — the Mifflin–St Jeor equation has separate constants for men and women and was validated on both sexes. Women generally have lower BMR than men of the same weight because of higher fat-to-muscle ratio and smaller organ mass; the formula bakes this in via the −161 sex term. Menstrual cycle phase can shift BMR by 2–10%, but that variation is small compared to typical day-to-day eating noise.

Not directly. Pregnancy adds roughly 340 kcal/day in the second trimester and 450 kcal/day in the third trimester. Breastfeeding adds roughly 450–500 kcal/day. These needs are individual and should be guided by your obstetrician or a registered dietitian — do not rely on a general TDEE calculator for nutrition planning during pregnancy or lactation.