Free Calorie Deficit Calculator
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Calorie Deficit Calculator

Estimate your TDEE, daily calorie target, and macros. See a visual weight-loss projection over time. Uses the Mifflin-St Jeor formula.

For informational purposes only. Not medical advice. Consult your healthcare provider before making dietary changes.

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Enter your details to see your TDEE, calorie target, macros, and weight-loss projection.

How the Calorie Deficit Calculator Works

This calculator uses the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate (BMR), then multiplies by an activity factor to estimate your Total Daily Energy Expenditure (TDEE). Your calorie target is TDEE minus your chosen deficit. A 500-calorie daily deficit yields roughly 1 pound of fat loss per week (since 1 lb of body fat contains approximately 3,500 calories).

Understanding Macros

Alongside your calorie target, the calculator provides suggested macronutrient splits. Protein is set high (0.7-1.0 g per pound of body weight) to support muscle preservation during a deficit. Fats are kept at a minimum of 20-25% of calories for hormonal health. Remaining calories come from carbohydrates.

Body-Fat Percentage and Deficit Size

People with higher body-fat stores can tolerate larger calorie deficits without significant muscle loss. If you enter your body-fat percentage, the calculator adjusts the recommended deficit aggressiveness. Those under 15% body fat (men) or 25% (women) are advised to use milder deficits to preserve lean mass.

Weight-Loss Projection

The projection graph shows an estimated weekly weight trajectory based on your chosen deficit. Real-world weight loss is not linear — expect fluctuations from water retention, hormonal cycles, and metabolic adaptation. The projection is a planning tool, not a guarantee.

Limitations

All calorie estimates are approximations. Individual metabolism varies based on genetics, muscle mass, hormones, sleep, stress, and medications. As you lose weight, your TDEE decreases — a phenomenon called metabolic adaptation. Recalculate every 10-15 pounds lost to keep your target accurate.

Frequently Asked Questions

How does a calorie deficit calculator work?

A calorie deficit calculator estimates your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation, which factors in your age, sex, height, weight, and activity level. It then subtracts a deficit amount to give you a daily calorie target for weight loss. A deficit of 500 calories per day typically leads to about 1 pound (0.45 kg) of weight loss per week.

What is TDEE and why does it matter?

TDEE stands for Total Daily Energy Expenditure — the total number of calories your body burns in a day including basal metabolism, physical activity, and the thermic effect of food. Knowing your TDEE helps you set a realistic calorie target: eat below your TDEE to lose weight, at your TDEE to maintain, or above to gain.

What is the Mifflin-St Jeor equation?

The Mifflin-St Jeor equation is considered the most accurate predictive equation for estimating Basal Metabolic Rate (BMR) in healthy adults. For men: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5. For women: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age - 161. BMR is then multiplied by an activity factor to estimate TDEE.

How does body-fat percentage affect calorie deficit recommendations?

People with higher body-fat percentages can typically sustain larger deficits more safely because they have more stored energy available. Those with lower body fat should use a smaller deficit to preserve muscle mass and maintain energy levels. Our calculator adjusts the recommended deficit range based on your estimated or entered body-fat percentage.

Is losing 2 pounds per week safe?

For most people, losing 1-2 pounds (0.45-0.9 kg) per week is considered safe and sustainable. A rate of 2 lbs/week requires a 1,000-calorie daily deficit, which can be aggressive for smaller individuals. Rapid weight loss may lead to muscle loss, nutritional deficiencies, and metabolic adaptation. Consult your healthcare provider before starting any aggressive deficit plan.