Calorie Deficit Calculator – 7,700 kcal/kg

One kilogram of body fat stores roughly 7,700 calories, so losing it requires burning that much more energy than you eat. This calculator takes your current weight, target weight and timeline, converts the gap into a daily deficit using the 7,700 kcal/kg rule, and subtracts it from your total daily energy expenditure to produce a target intake. It also sanity-checks the rate: research supports losing 0.25–1% of body weight per week, so a 90 kg lifter should lose 0.2–0.9 kg weekly. Worked example: dropping 8 kg in 16 weeks needs 8 × 7,700 ÷ 112 = 550 kcal per day below maintenance — a moderate, sustainable deficit.

1. 1

   Set your goal

   Enter current weight, target weight and how many weeks you have

2. 2

   Enter your TDEE

   Maintenance calories come from a TDEE calculation or two weeks of tracking

3. 3

   Get target intake

   The tool shows the daily deficit and the calories to eat every day

• 1

  Add a 100–150 kcal buffer for untracked weekend calories

• 2

  Recalculate the deficit every 4 kg lost — maintenance drops with weight

• 3

  Pair the deficit with 1.6–2.2 g/kg protein to keep muscle

• Cutting 1,000+ kcal instantly and rebounding within weeks

• Forgetting that maintenance falls 50–100 kcal per 5 kg lost

• Counting exercise calories as extra food and erasing the deficit

• Aiming for 1.5+ kg per week, which strips muscle and energy