Calorie Deficit Calculator
Find the daily calorie deficit needed to lose weight at your target rate and timeline with this free calorie deficit calculator in your browser.
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Result
Fill in the fields to see your result.
Estimate only — not medical or nutritional advice. Individual needs vary; consult a professional before making big changes.
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter sex, age, height, current weight and activity.
- Add your target weight and timeframe in weeks.
- Read the daily calorie target and weekly change.
How it works
Uses ~7,700 kcal per kg: daily change = (target − current) × 7,700 ÷ (weeks × 7). Target intake = TDEE + that change. Big rates trigger a safety note.
Worked example
Lose 5 kg in 10 weeks (TDEE 2,500). ≈ 550 kcal/day deficit → about 1,950 kcal/day (0.5 kg/week).
Tips
- Estimate only — not medical or nutritional advice. Individual needs vary.
Frequently asked questions
Is fast weight loss safe?
Losing more than ~1 kg/week is hard to sustain and can be unsafe — the tool warns you and suggests a longer timeframe.
Privacy?
Runs entirely in your browser. Your inputs are not saved or transmitted.
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- Macro Calculator
- Ideal Body Weight Calculator
- Weight Change Timeline Calculator
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Explore more in Health, Fitness, Nutrition & Body.
Cite this tool
Zerdly. (2026). Calorie Deficit Calculator. Retrieved from https://www.zerdly.com/tools/calorie-deficit-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.