Calories to Kilograms Converter

Convert a calorie surplus or deficit to the equivalent body weight change in kilograms, with estimated time to achieve at different daily rates.

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Weight change (kg)
−0.455
kilograms
Weight change (lbs)
−1.003
pounds
Time to achieve this loss
At 250 kcal/day deficit 14 days
At 500 kcal/day deficit 7 days
At 750 kcal/day deficit 5 days
1 kg of body fat ≈ 7,700 kcal

Body weight change estimates assume 7,700 kcal per kg of body fat. Actual results vary with individual metabolism, water retention, and body composition changes.

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Health — Nutrition

Calories to Kilograms Converter

How much weight does a given calorie surplus or deficit represent? This converter translates a calorie amount into an equivalent body weight change in kilograms, using the 7,700 kcal/kg conversion factor, and shows the time required at different daily calorie rates.

The 7,700 kcal per kilogram rule

Pure body fat contains approximately 9 kcal/g, but adipose tissue also contains water and connective tissue, reducing its energy density to roughly 7,700 kcal/kg. This is the basis for the well-known "3,500 calories per pound" rule (7,700 / 2.205 ≈ 3,500).

The 7,700 kcal/kg figure assumes all calorie excess or deficit translates into fat mass change. In reality, early weight loss includes water and glycogen changes, and metabolic adaptation slows progress over time.

Frequently asked questions

How many calories to lose 1 kg?

Based on the 7,700 kcal/kg model, a deficit of 7,700 kcal is required to lose 1 kg. At 500 kcal/day this takes approximately 15 days; at 250 kcal/day about 31 days.

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