See exactly how many calories to eat per day and how long it will take to reach your target weight — with a week-by-week projection.
These estimates are based on mathematical models and individual results will vary. Do not eat below 1,200 cal (women) or 1,500 cal (men) without medical supervision. Consult a healthcare professional before starting any weight loss program.
A calorie deficit means eating fewer calories than your body burns (your TDEE). When you consistently eat in a deficit, your body is forced to use stored energy — primarily body fat — to make up the difference. A deficit of 3,500 calories roughly equals one pound of fat loss.
This calorie deficit calculator works backward from your goal: it calculates your TDEE, subtracts the calories needed for your chosen weight loss rate, and tells you exactly how many calories to eat per day.
0.5 lb/week (250 cal deficit): The most sustainable approach. Minimal muscle loss, no hunger. Best for people within 10–15 lbs of their goal or those who struggle with restrictive diets.
1 lb/week (500 cal deficit): The sweet spot for most people. Noticeable progress without extreme restriction. This is what most dietitians recommend.
2 lbs/week (1,000 cal deficit): Aggressive but doable for people with significant weight to lose (30+ lbs). Not recommended for extended periods or for lean individuals — the risk of muscle loss, metabolic adaptation, and nutrient deficiency increases.
The week-by-week table above shows a linear projection, but real weight loss is never a straight line. You'll see fluctuations of 2–5 pounds day to day due to water retention, sodium intake, carb intake, hormonal cycles, and bowel contents. These are not fat changes.
What matters is the trend over 3–4 weeks. If the 4-week average is moving in the right direction, you're on track regardless of daily fluctuations. Weigh yourself daily at the same time and track the weekly average.
A 1,000 calorie daily deficit (2 lbs/week) is generally safe for overweight individuals for limited periods. However, if it drops your intake below 1,200 (women) or 1,500 (men) calories, it risks nutrient deficiencies and muscle loss. This calculator warns you if your target falls below these thresholds.
Some muscle loss is inevitable during a deficit, but you can minimize it by eating adequate protein (0.8–1g per pound of body weight), resistance training at least 2–3 times per week, and keeping the deficit moderate (15–25% below TDEE).
Yes. As you lose weight, your TDEE drops because a smaller body burns fewer calories. Recalculate every 10–15 pounds. This calculator uses your current weight, so revisit it as you progress.
Yes — a deficit is still a deficit whether you track it or not. Many people succeed by using portion control, eating more whole foods, and reducing processed food. However, tracking gives you precision and accountability, which is why it works well for most people.