Calorie Deficit Calculator

Calculate the exact daily calorie deficit required to reach your weight loss goal within your desired timeframe.

Required Daily Deficit833 kcal
Target Daily Intake1667 kcal
Total Weight to Lose20 lbs

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The Science of a Calorie Deficit

Weight loss is governed by thermodynamics. To lose weight, you must consume fewer calories than your body burns each day (your Total Daily Energy Expenditure, or TDEE). This state is known as a calorie deficit.

The 3,500 Calorie Rule

It takes a deficit of approximately 3,500 calories to lose one pound of body fat. Therefore, a daily deficit of 500 calories will result in roughly 1 pound of weight loss per week (500 * 7 = 3,500).

Worked Example

  1. Current Weight: 200 lbs
  2. Goal Weight: 180 lbs
  3. Weight to Lose: 20 lbs
  4. Timeline: 12 Weeks (84 Days)
  5. Total Calories to Burn: 20 * 3500 = 70,000
  6. Daily Deficit = 70,000 / 84 = 833 kcal/day.
  7. If TDEE is 2,500, Daily Target = 1,667 kcal.

Frequently Asked Questions

Is a 1,000 calorie deficit safe?

A 1,000 calorie daily deficit leads to 2 lbs of weight loss per week. While possible, it is aggressive and can lead to muscle loss and fatigue. A 500 calorie deficit is generally considered more sustainable.