Calorie Deficit Calculator

How the calorie deficit calculator works

Losing 1 kg of body weight takes a total deficit of roughly 7,700 kcal. That figure is the metric version of the classic 3,500 kcal per pound rule, and it is the basis for this calculator.

Enter your current weight, your goal and how many weeks you want to take. The calculator spreads the total deficit over those days and subtracts it from your maintenance calories, which you can get from the TDEE calculator.

The 7,700 kcal rule is a starting point, not a promise. Research by Kevin Hall and colleagues (The Lancet, 2011) shows weight loss slows over time as the body adapts, so expect the last kilograms to take longer than the first.

• A common guide is to lose no more than 0.5-1% of body weight per week. The calculator flags faster plans.
• Harvard Health advises not going below about 1,200 kcal a day for women and 1,500 kcal for men without medical supervision.
• Keep protein high (1.6-2.2 g per kg of body weight) and keep strength training while in a deficit so more of the loss comes from fat.