Calorie Deficit Calculator
Find your maintenance calories, pick a deficit, and see exactly how many calories to eat per day — and how fast you'll lose weight.
Frequently Asked Questions
What is a calorie deficit?
A calorie deficit means eating fewer calories than your body burns each day. Since roughly 3,500 calories equals one pound of body fat, a consistent daily deficit of 500 calories leads to about one pound of weight loss per week.
How big should my calorie deficit be?
A deficit of 250–500 calories per day is sustainable for most people and produces 0.5–1 lb of loss per week. Larger deficits (750–1,000) lose weight faster but are harder to maintain and increase the risk of muscle loss. Avoid eating below about 1,200 calories (women) or 1,500 calories (men) without medical supervision.
How are maintenance calories calculated?
Deficit Wiz uses the Mifflin-St Jeor equation, considered the most accurate standard formula. It estimates your basal metabolic rate from your sex, age, height, and weight, then multiplies by an activity factor to get your total daily energy expenditure (TDEE) — the calories you burn per day.
How much weight will I lose per week?
Multiply your daily deficit by 7 and divide by 3,500 to estimate weekly fat loss in pounds. A 500-calorie daily deficit is about 1 lb per week; 750 is about 1.5 lb per week. Actual results vary with water weight, adherence, and metabolic adaptation.
Why did my weight loss stall in a calorie deficit?
As you lose weight, your body burns fewer calories, so the same intake becomes a smaller deficit. Water retention can also mask fat loss for weeks. Recalculate your targets every 10–15 lbs lost, be consistent with tracking, and give any change at least 2–3 weeks before adjusting.