What is a calorie deficit?

A calorie deficit means eating fewer calories than your body burns over time. The calculator estimates maintenance calories and subtracts a selected deficit.

How fast should I lose weight?

CDC guidance describes gradual loss of about 1 to 2 pounds per week as more sustainable for many people. Medical context can change the right pace.

Why does my real weight trend differ from the calculator?

Water, glycogen, sodium, menstrual cycle changes, tracking error, activity changes and metabolic adaptation can all move the observed trend.

Calorie Deficit Calculator

Estimate maintenance calories, a calorie deficit or surplus, daily target calories and a rough weight-change timeline using US or metric inputs.

Calorie deficit inputs

Unit system

Metric

Sex used in formula

Male

Female

Age

Height (ft)

Height (in)

Current weight (lb)

Body fat optional (%)

Activity level

Pace

Goal

Lose weight

Maintain

Gain weight

Goal weight (lb, optional)

Calorie deficit and target calories

A calorie deficit calculator estimates maintenance calories, subtracts a selected deficit and shows the implied daily target. The result is a starting estimate, not a medical diet plan.

T D E E = B M R \times a c t i v i t y f a c t or

Maintenance calories are estimated from BMR and activity.

t a r g e t = T D E E - d e f i c i t

For weight gain, the same model adds a surplus instead of subtracting a deficit.

Trend-based adjustment

Healthy weight-loss guidance favors gradual, sustainable changes. Review several weeks of intake and 7-day average body-weight trend before making large adjustments.

Weight-loss pace

w ee k l y c han g e \approx \frac{d ai l y d e f i c i t \times 7}{7700}

Approximate energy model using kilograms; real weight change also includes water, glycogen and adaptation.

A 500 calorie daily deficit is a common rule-of-thumb starting point, but individual maintenance calories and safe targets vary.

Frequently Asked Questions

Sources and References

Calculations are based on the listed reference sources. Links open in a new tab.

Updated: June 2, 2026

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