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Calorie Deficit Calculator

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What Your Result Means

How This Calculator Works

You enter your current weight, goal weight, and either a known TDEE or your age, height, gender, and activity level. If no TDEE is provided, the tool computes your Basal Metabolic Rate using the Mifflin-St Jeor equation, then multiplies by an activity factor. It subtracts a daily calorie deficit (based on your chosen weekly loss rate and the 3,500-cal-per-pound approximation) to produce a daily calorie target and a timeline to reach your goal.

Quick Questions

Is the 3,500-calorie rule accurate?

It is a useful approximation for planning purposes. In practice, metabolic adaptation means the actual deficit needed per pound may increase over time, so progress can slow as you approach your goal.

What is a safe rate of weight loss?

Most health organizations suggest 1–2 pounds per week for sustainable fat loss. Losing weight faster can lead to muscle loss, nutritional deficiencies, and metabolic slowdown. Consult a healthcare provider for personalized advice.

Should I eat back exercise calories?

It depends on your activity level setting. If you selected a higher activity multiplier, your TDEE already accounts for exercise. Eating back additional exercise calories could reduce your deficit more than intended.

What if my daily target seems too low?

If the target falls below 1,200 cal/day (women) or 1,500 cal/day (men), consider choosing a slower weekly loss rate. Very low calorie diets should only be followed under medical supervision.

Sources

Method & review

MethodologyHow we calculate this Reviewed & Updated2026-04 Next review2027-04

Estimate only. Results reflect your inputs and standard formulas — they are not financial, tax, legal, health, or investment advice. Verify important decisions with a qualified professional.