Calorie deficit calculator
Mifflin-St Jeor equation · updated September 2026
The part most ab-workout sites won't tell you: no exercise removes the fat layer — a calorie deficit does. This calculator gives you your maintenance calories and a safe daily target. Pair it with any of our programs and the shape appears as the layer thins.
Calorie deficit calculator
Exercises shape the muscle — the deficit removes the fat over it. Find your numbers:
Estimates via the Mifflin-St Jeor equation; individual metabolism varies. This is general information, not medical or dietary advice — check with a professional before major changes, especially with health conditions.
FAQ
How big should my calorie deficit be?+
300–500 kcal/day (about 0.25–0.5 kg/week) is the sweet spot for most people: fast enough to see change, small enough to keep muscle and sanity. Bigger deficits usually backfire through hunger, muscle loss and rebound eating.
Why does the calculator cap my calories?+
Below roughly 1,200 kcal (women) or 1,500 kcal (men), it becomes very hard to get adequate protein and micronutrients, and muscle loss accelerates. If the math pushes you under the cap, choose a slower pace or add activity instead.
Do I have to count calories forever?+
No — most people count strictly for 2–4 weeks, learn what their portions actually contain, then manage by habit. The calculator gives you the target; awareness does the rest.
Where does the fat actually go first?+
You don't get to choose — fat leaves in a genetically determined order, and the belly is often last. That's why we pair this calculator with core training: the muscle is ready when the fat finally clears.