Weekly Weight Change Calculator
See how a daily gap between your calorie intake and maintenance turns into weekly and monthly weight change.
How it works
Daily balance = intake − maintenance · Weekly change = balance × 7 ÷ 7700 (kg)
Weight change over time is driven by the gap between what you eat and what you burn. Because roughly 7,700 kcal of energy balance corresponds to one kilogram of body mass, multiplying your daily calorie balance by seven and dividing by 7,700 gives the expected weekly change. A negative balance (a deficit) predicts loss; a positive one predicts gain.
Worked example
Eating 1,800 kcal against a 2,400 kcal maintenance is a 600 kcal daily deficit. Over a week that is 600 × 7 = 4,200 kcal, or 4,200 ÷ 7,700 ≈ 0.55 kg of loss per week.
Frequently asked questions
Why is my real weight change different from the estimate?
The 7,700 kcal-per-kg rule is an average. Day-to-day scale weight is dominated by water, glycogen, sodium and digestion, and metabolism adapts over weeks. Judge progress from a two-to-three-week trend, not a single weigh-in.
Is losing 1 kg a week realistic?
It requires a large ~1,100 kcal daily deficit, which is aggressive for most people and best reserved for those with higher body weight. A 0.25–0.75 kg/week loss is more sustainable and better preserves muscle.
Does this predict fat loss specifically?
No — it predicts change in total body mass. The proportion that is fat versus muscle depends on your protein intake, training and how aggressive the deficit is.
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Educational estimate only — not medical, dietary or fitness advice. Individual needs vary; consult a qualified clinician or registered dietitian before making health decisions.