What a calorie deficit is
A calorie deficit means consistently eating fewer calories than your body burns, which is the fundamental mechanism behind weight loss. Roughly 7,700 kcal of deficit corresponds to about 1 kg (2.2 lb) of fat loss.
How this calculator works
Enter your sex, age, height, weight, and activity level. The calculator estimates your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, then multiplies it by an activity factor to estimate your maintenance calories (TDEE). Based on your weekly weight loss goal, it calculates the daily calorie deficit needed and subtracts it from your TDEE to give a target daily calorie intake, with a floor applied so the suggested intake never drops below a generally recognized minimum (1,200 kcal for women, 1,500 kcal for men).
A moderate weekly loss goal of 0.25-1 kg (0.5-2 lb) is commonly considered sustainable; faster goals require larger deficits that can be harder to maintain and may affect nutrient intake. This tool is for general educational and planning purposes only and is not a substitute for professional medical or dietetic advice.