Calorie Deficit Calculator
Calculate the daily calorie deficit needed to reach your target weight in your desired timeline.
Safe and sustainable weight loss planning.
A calorie deficit occurs when you consume fewer calories than your body burns. This is the fundamental mechanism behind all fat loss — regardless of diet type, food choices, or eating patterns. Creating a consistent daily deficit forces the body to draw on fat stores for energy.
Core formulas: TDEE (Total Daily Energy Expenditure) = BMR × Activity Multiplier Calorie Deficit = TDEE − Daily Calorie Intake Weekly Deficit = Daily Deficit × 7 Estimated Weekly Fat Loss (lbs) = Weekly Deficit ÷ 3,500
BMR (Basal Metabolic Rate) — Mifflin-St Jeor formula (most accurate): Male: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5 Female: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Activity multipliers:
- Sedentary (desk job, no exercise): BMR × 1.2
- Lightly active (1–3 days/week exercise): BMR × 1.375
- Moderately active (3–5 days/week): BMR × 1.55
- Very active (6–7 days/week intense exercise): BMR × 1.725
- Extra active (physical job + daily exercise): BMR × 1.9
What each variable means:
- BMR — the calories your body burns at complete rest just to maintain organ function (breathing, heartbeat, digestion).
- TDEE — your actual daily calorie burn including all movement and exercise.
- 3,500 calories — the approximate caloric value of 1 pound of stored body fat. Burn 3,500 more calories than you eat = lose ~1 lb of fat.
- Deficit range: 250–500 cal/day = 0.5–1 lb/week loss (sustainable). 750–1,000 cal/day = 1.5–2 lbs/week (aggressive but feasible). More than 1,000 cal/day deficit risks muscle loss and metabolic adaptation.
Worked example: 35-year-old male. Weight: 90 kg. Height: 178 cm. Moderately active (gym 4× week).
BMR = (10×90) + (6.25×178) − (5×35) + 5 = 900 + 1,112.5 − 175 + 5 = 1,842.5 calories TDEE = 1,842.5 × 1.55 = 2,856 calories/day
For 1 lb/week loss: Deficit = 500 cal/day → Eat 2,356 calories/day For 1.5 lbs/week: Deficit = 750 cal/day → Eat 2,106 calories/day
Estimated fat loss at 500 cal/day deficit over 12 weeks: 12 × 1 lb = ~12 lbs (actual varies based on metabolic adaptation and water retention).