Calorie Deficit Calculator
Uses the Mifflin-St Jeor equation (the gold-standard BMR formula) to calculate your maintenance calories, then adjusts for your goal. A 500 kcal daily deficit produces roughly 0.5 kg of fat loss per week.
Frequently Asked Questions
What is a calorie deficit and why does it cause weight loss?+
A calorie deficit means you consume fewer calories than your body burns. When this happens, your body draws on stored fat for energy, causing fat loss. A deficit of approximately 7,700 kcal leads to roughly 1 kg of fat loss.
What is TDEE?+
TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns in a day, accounting for your basal metabolic rate (BMR) plus all physical activity. To lose weight, eat below your TDEE; to gain, eat above it.
How large a calorie deficit is safe?+
A deficit of 300–500 kcal per day is generally considered safe and sustainable, producing 0.3–0.5 kg of weight loss per week. Deficits larger than 1,000 kcal/day can cause muscle loss, nutritional deficiencies, and metabolic slowdown.
Does the Mifflin-St Jeor formula work for everyone?+
The Mifflin-St Jeor equation is the most validated BMR formula for most adults but is an estimate, not a precise measurement. Actual metabolic rates can vary by 10–15% from the formula. If you are not losing weight at the calculated deficit, reduce intake by another 100–150 kcal and reassess after two weeks.