Calorie deficit calculator
Choose a sustainable rate of loss and get calorie, protein, fat and carb targets with safety floors built in.
Maintenance
2,500 kcal
starting estimate
Daily target
2,060 kcal
-440 kcal/day
Protein
160 g
2 g/kg
Fat / Carbs
57 / 227 g
How this was calculated: Maintenance ≈ 2500 kcal (estimated with the Mifflin-St Jeor formula and your activity). A -0.5%/week target at 80kg needs a 440 kcal daily deficit. Protein 2 g/kg = 160 g. BMR 1758 kcal. Fat is at least 0.6 g/kg; carbs fill the rest. This is a starting estimate — real expenditure varies by a few hundred calories.
Estimates for healthy adults, not medical advice. If you are pregnant, have a medical condition or a history of disordered eating, speak to a qualified professional first.
Worked example
At 80kg and a 2,500 kcal maintenance, a 0.5%-a-week target means losing about 0.4kg a week. That needs a deficit of roughly 440 kcal a day (0.4kg × 7,700 kcal ÷ 7), so the target is about 2,060 kcal with 160g of protein. If after three weeks your 7-day average is falling 0.4kg a week, change nothing.
Common questions
- How big should my calorie deficit be?
- For most people a rate of 0.5–1% of bodyweight per week is a sustainable range. Slower rates make it easier to keep strength and muscle, especially if you are already lean.
- Why is my weight up even though I am in a deficit?
- Water, salt, carbohydrate intake and digestion can move the scale by 1–2kg day to day. Judge progress on a 7-day average over at least two weeks, not on a single weigh-in.
- Will I lose muscle in a deficit?
- Keeping protein high, continuing resistance training and avoiding very aggressive deficits are the best-supported ways to preserve muscle and strength while losing fat.
- Is there a minimum calorie intake?
- This calculator will not go below 1,200 kcal (women) or 1,500 kcal (men). Very low intakes should only be followed under medical supervision.
Lose fat. Keep your muscle. Adjust only when the trend says so.
DeficitCoach starts from these numbers, then learns from what you actually log — and tells you why every time it changes something.
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