Calorie Deficit Calculator — Weight Loss

Calculate your daily calorie deficit and see how much weight you'll lose. Enter your TDEE and daily intake for instant results.

Your Total Daily Energy Expenditure

How many calories you eat daily

Optional: For weight loss timeline

Deficit = TDEE - Daily Calorie Intake; Weekly Weight Loss = (Deficit × 7) ÷ 3,500 (calories per lb of fat); Monthly = Weekly × 4.33; Safe deficit: 250-750 cal/day; Minimum intake: 1,200 cal (women), 1,500 cal (men)
Example: TDEE = 2,200 cal, Intake = 1,700 cal; Deficit = 500 cal/day (23% of TDEE); Weekly loss: ~1.0 lb; Monthly loss: ~4.3 lbs; Time to lose 20 lbs: 20 weeks; Status: Safe and sustainable ✓

What is a calorie deficit and how does it cause weight loss?

A calorie deficit occurs when you consume fewer calories than your body burns. When in deficit, your body taps into stored fat for energy. 1 pound of body fat ≈ 3,500 calories. A 500-calorie daily deficit = 3,500 calorie weekly deficit = approximately 1 lb of fat loss per week. Your body burns calories through: BMR (Basal Metabolic Rate): 60-70% of total burn (breathing, organ function), TEF (Thermic Effect of Food): 10% (digestion), NEAT (Non-Exercise Activity): 15-30% (fidgeting, walking), Exercise: 5-10% (structured workouts).

How large should my calorie deficit be for safe weight loss?

Recommended deficit ranges: Conservative (0.5 lb/week): 250 cal/day deficit, safest, least muscle loss, Moderate (1 lb/week): 500 cal/day deficit, most recommended, sustainable, Aggressive (1.5 lb/week): 750 cal/day deficit, faster results but harder to maintain, Very aggressive (2 lbs/week): 1,000 cal/day deficit, only for obese individuals under medical supervision. Minimum calorie intake: Women: never below 1,200 cal/day, Men: never below 1,500 cal/day. Going below these thresholds risks nutrient deficiencies, muscle loss, metabolic slowdown, and disordered eating.

How do I calculate my calorie deficit?

Step 1: Calculate your TDEE (Total Daily Energy Expenditure) using a TDEE calculator or the Mifflin-St Jeor equation. Step 2: Decide your weight loss goal (0.5, 1, or 1.5 lbs/week). Step 3: Subtract the appropriate deficit: 250, 500, or 750 calories. Step 4: Ensure your target calories don't go below minimum thresholds (1,200 for women, 1,500 for men). Example: If your TDEE is 2,200 calories and you want to lose 1 lb/week: Target = 2,200 - 500 = 1,700 cal/day. Track your actual intake with a food diary app for at least 2 weeks to ensure accuracy.

Why am I not losing weight even in a calorie deficit?

Common reasons for stalled weight loss despite being in a "deficit": Underestimating intake: Studies show people underestimate food intake by 30-50%, Overestimating TDEE: Fitness trackers overestimate calorie burn by 20-90%, Water retention: High sodium, stress, hormones, or new exercise can mask fat loss, Adaptive thermogenesis: Metabolism slows 5-15% during dieting beyond predicted, Medical conditions: Hypothyroidism, PCOS, insulin resistance can reduce TDEE, Medications: Antidepressants, beta-blockers, steroids cause weight gain/retention. Solutions: Weigh and measure ALL food, Use a more conservative TDEE estimate, Track for 3-4 weeks before adjusting, Consider bloodwork for underlying issues.