TDEE Calculator
Calculate your Total Daily Energy Expenditure - the calories your body burns per day. Then see your target calories for weight loss. Especially useful for understanding how much your appetite needs to drop on a GLP-1.
Your stats
Your numbers
Calculated with the Mifflin-St Jeor equation - the most accurate BMR formula in non-athlete populations.
Worked example: 175-lb sedentary adult starting Wegovy
Take a 175-lb, 5'6", 42-year-old sedentary woman starting Wegovy at the 0.25 mg initiation dose. Mifflin-St Jeor BMR is roughly 1,410 cal/day. Sedentary TDEE (BMR × 1.2) is about 1,690 cal/day. To lose 1 lb/week she needs a 500-cal/day deficit - so her target-loss calorie budget is about 1,190 cal/day. That is below her BMR, which is exactly where GLP-1s put most people at their maximum dose.
The practical implication is that hitting 1,190 becomes harder than staying under it. By week 8 on Wegovy, appetite suppression from the 1.0-1.7 mg titration doses often drops spontaneous intake to 1,000-1,200 cal/day without any active restriction. That produces the 1 lb/wk loss target automatically. What often goes wrong: protein drops too - and at 175 lb goal weight, she needs roughly 120 g protein per day minimum to preserve muscle, which requires deliberate effort at 1,200 cal/day. Two shakes plus a chicken-and-yogurt-heavy meal gets there; skipping a meal because you are not hungry does not.
How GLP-1s and TDEE interact
GLP-1 medications like Wegovy, Ozempic, and Zepbound work primarily by reducing your appetite and slowing gastric emptying, which makes you eat less and feel full faster. They don't directly increase your calorie burn - they decrease your intake.
So your TDEE stays roughly the same. What changes is how easy it is to eat in a deficit. People on Wegovy commonly report eating 600–1,000 fewer calories per day without trying, producing the 14.9% weight loss seen in the STEP-1 trial.
Quick targets
- 1 lb/week loss = 500-cal/day deficit from TDEE
- 1.5 lb/week loss = 750-cal/day deficit (aggressive)
- 2 lb/week loss = 1,000-cal/day deficit (only short-term, with provider oversight)
- Maintenance = eat your TDEE
Should you eat below your BMR?
On a GLP-1, many people accidentally eat below their BMR (basal metabolic rate - what your body burns at rest) because of suppressed appetite. Sustained intake below BMR can cause muscle loss, fatigue, and metabolic slowdown that will follow you off the drug. The practical rule: aim for a caloric floor at or above BMR every day even if your target-loss budget is below it. Some days you will be under; long-run average should sit at BMR or above. If your appetite is so suppressed that you cannot hit BMR even with protein shakes and evening-only eating, talk to your prescriber about a dose adjustment or a titration pause - that is a well-recognized signal to slow the ramp, not something to power through.
A related trap is the NIH-authoritative BMR floor: the Institute of Medicine, NIH, and most registered dietitians treat 1,200 cal/day for women and 1,500 cal/day for men as the practical minimum below which micronutrient adequacy becomes extremely hard to achieve without a supervised very-low-calorie diet plan. If the calculator returns a target-loss number below those thresholds, target the threshold instead and accept that weight loss will be somewhat slower.
Frequently asked questions
Should I eat back my exercise calories on a GLP-1?
Usually no. Two reasons. First, on a GLP-1 your appetite is already suppressed enough that most people struggle to hit their target-loss calorie floor - eating back exercise calories often pushes you above maintenance without you noticing. Second, wearable-tracker calorie-burn estimates for exercise are systematically over-estimated, sometimes by 30-40%. If you are doing serious resistance training and your protein intake is dropping below ~0.7 g/lb of goal weight, that is the signal to raise floor calories - not the elliptical.
What if I am nauseous and cannot hit my calorie target?
Very common on the first few weeks of each dose escalation. Try smaller more frequent meals (5-6 mini-meals), high-protein liquids (Fairlife, Premier, plain Greek yogurt smoothies), and eating in the evening once early-day peak-nausea has passed. Persistent inability to hit even your BMR after two weeks at a dose is a call-your-prescriber signal - they may slow your titration or pause an increase. Do not white-knuckle it - sustained caloric intake below BMR causes muscle loss, fatigue, and eventually a metabolic slowdown that undoes the drug's advantage.
Does my TDEE change as I lose weight?
Yes. TDEE is a function of your current body mass, so as you drop weight you burn fewer calories at rest and during activity. A patient starting at 250 lb and ending at 200 lb will burn roughly 300-400 fewer calories per day at goal weight than at starting weight - which is why an early deficit that produced 2 lb/wk stops producing anything by month 6-9 on the same calorie budget. Recalculate every 15-20 lb of loss so your target-loss calories reflect your current body, not your starting body.
What if I am strength training on a GLP-1?
Prioritize protein and floor calories. The single biggest concern for GLP-1 patients doing resistance training is muscle-loss during the weight-loss phase - studies of Wegovy and Zepbound trial populations found ~25-40% of the total weight lost was lean mass in patients who did not train. Two rules that reduce that: (1) hit at least 0.7-1.0 g protein per pound of goal weight per day, non-negotiable, use shakes if solid food is impossible on the drug; (2) train each muscle group 2-3x/week with progressive overload. Cardio does not preserve muscle - only resistance training does.
Is BMR the same as TDEE?
No. BMR (basal metabolic rate) is what your body burns at complete rest - the metabolic cost of keeping you alive if you did not move at all for a day. TDEE is BMR × an activity multiplier that accounts for movement, digestion, and exercise. Sedentary TDEE is BMR × 1.2, lightly active is BMR × 1.375, active is BMR × 1.55, very active is BMR × 1.725. The calculator above computes both - eating below BMR is what damages metabolism; eating below TDEE but above BMR is where healthy weight loss lives.
Related guides
GLP-1 cost cheat sheet
Free PDF: every drug, every payment channel, every cost - so you can find the cheapest path to your weight-loss goal.