Calorie deficit/surplus calculator
Δweight (kg) ≈ Δkcal × days ÷ 7,700 kcal/kg fat tissue.
- Daily deficit/surplus
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- Total over period
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- Weight change (kg)
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- Weight change (lb)
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- Per week
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Heuristic only: actual fat/muscle balance depends on training, protein intake, and adherence. ~0.5–1% body weight per week is a sustainable rate.
How to use Calorie deficit/surplus calculator
- Enter your target weight change and timeframe.
- The calculator estimates the daily calorie deficit or surplus needed, using the standard approximation that roughly 7,700 kcal ≈ 1 kg of fat tissue.
Limitations
- This is a standard estimation formula, not personalized medical advice — actual results vary by individual metabolism, activity level, and body composition changes over time.
About this tool
Calorie deficit/surplus calculator is a single-purpose utility on instant.tw, a free toolbox of calculators, converters, generators, and quick lookups. Everything works in your browser — nothing is uploaded, nothing is stored on a server unless explicitly noted.
Category: Health & Fitness. Browse more Health & Fitness tools.