Calorie Calculator

Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a full day, including everything your Basal Metabolic Rate (BMR) does not cover: digesting food, walking around, fidgeting, working, exercising, and every other form of movement and activity. It is the number that actually determines whether you gain, maintain, or lose weight, because weight change is governed by the balance between calories eaten and calories burned — TDEE is the "burned" side of that equation. This calculator gets to TDEE in two steps: first it estimates your BMR using the Mifflin-St Jeor equation (the same formula used by the standalone BMR Calculator, and the equation most validation studies since 1990 have found most accurate for the general population), and then it multiplies that BMR by an activity multiplier that reflects how much you move in a typical week. The five activity levels used here follow the standard tiers popularised by the Harris-Benedict and Mifflin-St Jeor research literature and used by most nutrition calculators: Sedentary (×1.2) covers little to no exercise and a desk job; Lightly Active (×1.375) covers light exercise or sports 1-3 days a week; Moderately Active (×1.55) covers moderate exercise 3-5 days a week; Very Active (×1.725) covers hard exercise 6-7 days a week; and Extra Active (×1.9) covers very hard daily exercise combined with a physically demanding job or twice-daily training. Picking the right tier is the single biggest source of error in any TDEE estimate — most people, when self-assessing, tend to overestimate how active they actually are, which is worth bearing in mind if your real-world weight trend does not match what the calculator predicts after a few weeks. Once TDEE is known, weight change targets follow from a well-established approximation: roughly 3,500 kilocalories corresponds to about one pound (0.45 kg) of body fat, so a sustained daily deficit or surplus translates fairly predictably into a weekly rate of change. This tool shows six goals built on that relationship: Extreme weight loss (TDEE − 1,000 kcal/day, roughly 2 lb/week), Weight loss (TDEE − 500 kcal/day, roughly 1 lb/week), Mild weight loss (TDEE − 250 kcal/day, roughly 0.5 lb/week), Maintain weight (TDEE), Mild weight gain (TDEE + 250 kcal/day), and Weight gain (TDEE + 500 kcal/day). The 3,500-kcal rule is a useful planning approximation rather than a precise biological constant — it was derived from the energy density of body fat and does not perfectly hold at every point of a diet, particularly for larger or more sustained deficits, where metabolic adaptation (the body's BMR and NEAT — non-exercise activity thermogenesis — both tend to drop somewhat during sustained dieting) means the real-world rate of loss often slows over time even at a constant calorie intake. A calorie deficit larger than roughly 1,000 kcal/day below TDEE — the "Extreme weight loss" tier — is generally not recommended without medical supervision, since very large deficits increase the risk of muscle loss, nutrient deficiency, fatigue, and difficulty sustaining the plan long enough to matter. Most dietitians recommend a moderate deficit (the 250-500 kcal/day tiers) precisely because it is realistic to sustain for months, which matters more for long-term results than the size of any single week's deficit. This calculator gives a starting estimate to plan from, not a guarantee — actual results depend on how accurately you log food intake, how your body responds individually, and how consistent you are day to day. If you have a medical condition, are pregnant or breastfeeding, or are underweight, talk to a doctor or registered dietitian before using any calorie target from a generic calculator like this one.