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).
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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