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Find the calories you burn per day (your maintenance), a target to lose weight at your chosen pace, and — unlike generic calculators — a trial-grounded projection of what a GLP‑1 like Wegovy or Zepbound adds on top. Want the deficit-first view? Use the calorie deficit calculator.
Enter your age, height, and weight above to see your BMR, maintenance calories, and a GLP-1 weight-loss projection.
BMR uses the Mifflin-St Jeor equation. Estimates are general nutrition information, not medical or dietary advice. Inputs stay on your device — nothing is sent anywhere.
Your TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns in a day. It has four parts: your BMR (calories burned at rest, ~60–70% of the total), the thermic effect of food (~10%), everyday non-exercise movement, and deliberate exercise. Eat below your TDEE and you lose weight; eat above it and you gain.
We calculate BMR with the Mifflin-St Jeor equation, the standard most registered dietitians use because it tracks modern body composition better than the older Harris-Benedict formula. Then we multiply BMR by an activity factor:
| Activity level | Multiplier | Who it fits |
|---|---|---|
| Sedentary | × 1.2 | Desk job, little or no exercise |
| Lightly active | × 1.375 | Light exercise 1–3 days/week |
| Moderately active | × 1.55 | Moderate exercise 3–5 days/week |
| Very active | × 1.725 | Hard exercise 6–7 days/week |
| Athlete | × 1.9 | Physical job or twice-daily training |
One pound of fat holds roughly 3,500 calories, so a daily deficit of ~500 calories loses about 1 lb per week. The calculator shows three paces — mild, moderate, and aggressive — and floors every target at ~1,200 calories/day, because eating lower than that long-term usually backfires (muscle loss, metabolic slowdown, and rebound).
The hard part of any deficit is holding it — hunger fights back. GLP-1 medications (semaglutide as Wegovy, tirzepatide as Zepbound) work by blunting appetite, so the same deficit takes far less willpower. In the STEP 1 trial, Wegovy produced about 15% average total weight loss at 68 weeks; in SURMOUNT-1, Zepbound reached about 21% at 72 weeks. The calculator projects those percentages onto your starting weight — as trial averages, not a promise. See the week-by-week projection tool for the full curve, or compare the two head-to-head in Wegovy vs Zepbound.