Calorie Deficit Calculator for Weight Loss
Plan a safe daily calorie deficit to hit your target weight by a target date.
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About the Calorie Deficit Calculator for Weight Loss
Calorie Deficit Calculator works out the daily calorie shortfall you need to run in order to lose a target amount of weight by a target date. It uses the well-validated figure of ~7,700 kcal per kilogram of body fat.
How to use
- Enter your current weight and goal weight (both in kg).
- Enter the number of weeks until your target date.
- Click Calculate for daily and weekly deficit numbers.
Benefits & key features
- Personalised to your actual weight and time-frame.
- Flags unrealistic targets (>1 kg/week) automatically.
- Honest, evidence-based math — no 'lose 10 kg in a week' fantasy.
- Works with the TDEE calculator for a full eating plan.
Pro tip
A sustainable deficit is 500–750 kcal/day (~0.5-0.75 kg/week). Much faster than that and you'll lose muscle, hair and motivation.
Why choose toolsfy for Health & Fitness tools?
A BMI calculator that harvests your email address, a TDEE estimator that upsells coaching — the health-and-fitness web is riddled with dark patterns. toolsfy's tools compute the same peer-reviewed equations (Mifflin-St Jeor for TDEE, WHO BMI bands, U.S. Navy body-fat formula) without asking for anything more than the numbers needed to run the math.
Common use cases
- Personal trainers running quick BMI and body-fat estimates for new clients during their first consultation, with nothing logged or stored.
- Home cooks planning a short calorie-deficit cycle and wanting the daily target in plain numbers rather than a vague "app score".
- Patients preparing for a doctor's appointment by converting a mg/dL blood-sugar reading into mmol/L (or vice versa) before their consult.
Frequently asked questions
Is this medical advice?
No. These tools are educational and use standard published equations. Always discuss real health decisions with a licensed clinician.
How accurate are estimates like TDEE or body fat?
They are good screening estimates for a general adult population. Individual metabolism can vary ±10–15%, so treat the number as a starting point, not a target.
Do you store my weight, height or health data?
Never. The values are only used inside this tab to compute the result. Close the tab and every trace is gone.