Free Tool · Metabolic Health

Calorie deficit
calculator.

Find the calories you burn in a day, then the intake that produces steady fat loss — without dropping so low that you lose muscle along with it.

Your numbers

Resting metabolic rate: 1,503 cal/day
Maintenance calories (TDEE): 2,067 cal/day

GoalDaily caloriesDeficit
Maintain weight2,067No change
Slow loss (≈0.5 lb/week)1,817−250 cal/day
Standard loss (≈1 lb/week)1,567−500 cal/day
Faster loss (≈1.5 lb/week)1,317−750 cal/day

Estimates use the Mifflin-St Jeor equation. This is general education, not medical advice.

How it works

Why the deficit matters less than what's in it.

A calorie deficit is the requirement for fat loss — but the size of the deficit is only half the picture. Two people eating 1,600 calories a day can end up with very different bodies depending on protein intake, training, and sleep. Aggressive deficits reliably produce faster scale movement and reliably cost more lean muscle, which lowers your metabolic rate and makes the weight easier to regain.

In practice, a 15–25% deficit below maintenance, combined with adequate daily protein and two or three resistance sessions a week, is what keeps the loss mostly fat. Add enough fiber and the deficit becomes far easier to hold, because fullness stops being the limiting factor.

If you're on semaglutide or tirzepatide, the deficit usually arrives on its own — appetite drops sharply and many people unintentionally eat far under maintenance. In that case this number is a floor to eat up to, not a ceiling. Our GLP-1 weight loss calculator estimates the pace of loss to expect on therapy.

Questions

Calorie deficit FAQs.

About 500 calories a day averages a pound a week; 250 a day averages half a pound. Going much beyond 25% below maintenance usually costs lean muscle and gets hard to sustain.
Total daily energy expenditure — everything you burn in a day: resting metabolism, digestion, daily movement, and exercise. Eating at your TDEE holds weight steady.
Roughly a 1,000-calorie daily deficit, which is only appropriate if your maintenance is high enough that you still land above about 1,200 calories (women) or 1,500 (men).
Usually under-reported intake, water retention from sodium or new training, or an overestimated activity level. If weight is flat across three to four consistent weeks, the estimate is likely too high — drop it by about 200 calories and reassess.
Yes, though the usual problem on a GLP-1 is eating too little rather than too much. Use the maintenance number to make sure you're not chronically far below it.
It's the most accurate of the common predictive equations — typically within about 10% — but it's still an estimate. Real-world weight data over three to four weeks beats any formula.
Beyond the calculator

Numbers are a starting point. Labs tell the real story.

Insulin resistance, thyroid function, and medication history all change what a workable deficit looks like. We build the plan around your labs.

Book a free consult