Calorie Deficit Calculator

Calculate the exact calorie deficit needed to reach your weight loss goal. Enter your TDEE, current weight, target weight, and timeline to get your daily calorie target and weekly loss rate.

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Daily Calorie Deficit
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Daily Calorie Target —
Weight Loss Rate —
Total Weight to Lose —
Extended More scenarios, charts & detailed breakdown ▾
lbs
lbs
weeks
cal/day
Daily Deficit
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Calorie Target —
Weekly Loss Rate —
Total to Lose —
Professional Full parameters & maximum detail ▾
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Body Composition

Lean Body Mass —
Est. Body Fat % at Goal —

Calorie Targets

Daily Deficit —
Calorie Target —
BMR Safety Check —

Macros at Deficit

Minimum Protein —
Fat Target —
Carb Target —

Protocol Notes

Metabolic Adaptation Note —
Recommended Diet Breaks —

How to Use This Calculator

  1. Enter your current weight and target weight in pounds.
  2. Enter your timeline in weeks.
  3. Enter your TDEE (use the TDEE Calculator if you don't know it).
  4. The calculator shows your daily calorie deficit, daily target, and weekly loss rate. Use the Professional tab for macro targets and BMR safety checks.

Formula

Daily Deficit = (Total Weight to Lose × 3,500 cal/lb) ÷ (Weeks × 7)

Daily Calorie Target = TDEE − Daily Deficit

Weekly Loss Rate = (Daily Deficit × 7) ÷ 3,500

Example

Example: Goal: lose 20 lbs in 20 weeks. TDEE: 2,500 cal/day. Total deficit needed: 20 × 3,500 = 70,000 cal. Daily deficit = 70,000 ÷ 140 = 500 cal/day. Calorie target: 2,500 − 500 = 2,000 cal/day.

Frequently Asked Questions

  • A calorie deficit occurs when you consume fewer calories than your body burns. Since one pound of fat equals approximately 3,500 calories, a deficit of 500 calories per day leads to roughly 1 pound of weight loss per week.
  • A standard calorie calculator tells you how many calories to maintain your weight (TDEE). This calculator specifically computes the deficit needed to reach a target weight by a specific date, accounting for weekly loss rate and BMR safety.
  • For most adults, eating below 1,200 calories (women) or 1,500 calories (men) risks nutrient deficiencies and muscle loss. This calculator flags when your target dips below your BMR. Extend your timeline if needed.
  • Over time, the body adapts to a calorie deficit by slowing metabolism, making weight loss harder. Diet breaks (eating at maintenance for 1-2 weeks every 6-8 weeks) help prevent metabolic adaptation.
  • Use the TDEE Calculator on this site. It factors in your BMR (basal metabolic rate) and activity level to estimate your Total Daily Energy Expenditure.

Related Calculators

⚡ TDEE Calculator 🔥 Calorie Calculator 💓 BMR Calculator 🥗 Macro Calculator
Sources & References (5) ▾
  1. Hall KD et al. — Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826-837 — The Lancet
  2. Doucet E et al. — Evidence for the existence of adaptive thermogenesis during weight loss. Br J Nutr. 2001;85(6):715-723 — British Journal of Nutrition
  3. Mifflin MD et al. — A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247 — American Journal of Clinical Nutrition
  4. NIH — Body Weight Planner (based on Hall KD et al. mathematical model) — NIH / NIDDK
  5. Academy of Nutrition and Dietetics — Position of the Academy: Interventions for the Treatment of Overweight and Obesity in Adults (2016) — Academy of Nutrition and Dietetics