Mifflin-St Jeor formula
3 weight loss paces
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Macro targets included
Weight Loss Science

Your exact
calorie target
to lose weight

Enter your stats, pick your pace — get your daily calorie target, weekly loss projection, and macro breakdown, all in one calculation.

Slow · Moderate · Aggressive Macro targets included BMR + TDEE based
85kg 82kg 79kg Wk 1 Wk 5 Wk 9 Wk 12 DAILY TARGET — kcal WEEKLY LOSS PROJECTION Enter your details below →
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Calorie Deficit Calculator

Your daily calorie target to lose weight

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Your daily calorie target
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Suggested daily macros at your target

Based on the Mifflin-St Jeor equation. Individual metabolism varies by up to ±10%. Adjust intake by 100–200 kcal based on real results over 2–3 weeks. Do not eat below 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision.

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Body Mass Index
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Pro tip

Weigh yourself at the same time each morning after using the bathroom. Track a 7-day average — daily fluctuations of 1–2 kg from water and food are normal and don't reflect fat change.

What is a calorie deficit?

A calorie deficit occurs when you consume fewer calories than your body burns in a day. Your body makes up the shortfall by drawing on stored energy — primarily fat — which results in weight loss over time. The size of the deficit determines how quickly you lose weight, with larger deficits producing faster but riskier results.

Your total daily calorie burn — known as TDEE (Total Daily Energy Expenditure) — includes your resting metabolism, the energy used to digest food, and all physical activity. A deficit is created by eating below this number through diet, increasing it through exercise, or both.

How much deficit is safe?

A deficit of 300–500 calories per day is the most widely recommended range. At 500 calories per day, you theoretically lose about 0.5 kg per week — a pace that most research associates with good fat loss while preserving muscle mass. Deficits larger than 1,000 calories per day carry significant risks of muscle loss, nutritional deficiency, and metabolic adaptation.

Calorie deficit by weight loss pace

PaceDaily deficitWeekly lossBest for
Slow~250 kcal~0.25 kgAthletes, muscle preservation
Moderate~500 kcal~0.5 kgMost people, sustainable
Aggressive~750 kcal~0.75 kgShort-term, needs monitoring

Why faster isn't always better

Large calorie deficits often lead to muscle loss because the body breaks down protein for energy when calories are severely restricted. Since muscle is metabolically active tissue, losing it lowers your TDEE — making future fat loss harder. A slower deficit combined with adequate protein and resistance training produces better body composition results than aggressive restriction.

Frequently asked questions

A deficit of 300–500 calories per day is the most sustainable range for most people, producing 0.25–0.5 kg of fat loss per week. Deficits larger than 1,000 calories per day risk muscle loss, nutrient deficiencies, and metabolic adaptation. Slower deficits preserve more muscle and produce better long-term results.
One kilogram of fat contains approximately 7,700 calories. To lose 1 kg per week you need a daily deficit of around 1,100 calories — which is aggressive and not recommended for most people. A safer target is 0.5 kg per week, requiring a deficit of roughly 550 calories per day.
Yes. Very large calorie deficits can trigger metabolic adaptation — your body reduces its energy expenditure in response to prolonged restriction. This is why weight loss often plateaus despite continued dieting. Moderate deficits combined with adequate protein and resistance training minimise this effect.
It depends on your activity level setting. If you selected a multiplier that already accounts for your workouts, your TDEE already includes those calories and you should not add them back. If you chose sedentary and are tracking exercise separately, adding estimated exercise calories to your daily target is appropriate.
Protein intake is especially important in a deficit to preserve muscle mass. Most research supports 1.6–2.2 grams of protein per kilogram of bodyweight per day when dieting. Higher protein also increases satiety, making it easier to stick to your calorie target.
Most health organisations recommend no less than 1,200 calories per day for women and 1,500 for men, as intakes below these levels make it very difficult to meet nutritional requirements. Eating at or below your BMR for extended periods risks nutrient deficiencies and muscle loss.