Calorie Deficit Calculator

Weight loss occurs when you expend more energy than you consume. This is known as a calorie deficit. Our calculator helps you determine exactly how many calories you need to cut to achieve your target weight loss rate.

The Science of Fat Loss

Human fat tissue contains approximately 7,700 kilocalories (kcal) of energy per kilogram (roughly 3,500 kcal per pound).

The Deficit Formula

To calculate the weekly calorie deficit required to lose a target amount of weight ($W$ in kg) per week:

$\text{Weekly Deficit} = W \times 7700$

To find your Daily Calorie Target ($T$) based on your Total Daily Energy Expenditure ($TDEE$):

$T = \text{TDEE} - \left( \frac{\text{Weekly Deficit}}{7} \right)$

Frequently Asked Questions

Is a larger calorie deficit better?

No. While a larger deficit leads to faster initial weight loss, extreme deficits (greater than 1000 calories/day) can lead to muscle loss, nutrient deficiencies, gallstones, and a slowed metabolic rate. A sustainable deficit of 300-500 calories per day is generally recommended.

Why am I eating in a deficit but not losing weight?

If the scale isn't moving after several weeks, you are likely not in a true deficit. This usually happens due to underestimating portion sizes (eating more calories than you think) or overestimating your TDEE (assuming you burn more calories through exercise than you actually do).

Do I have to track calories forever?

Not necessarily. Tracking calories is a fantastic educational tool to understand portion sizes and macronutrient density. Many people track strictly for a few months, then transition to intuitive eating once they have a good visual grasp of their dietary needs.