This calorie deficit calculator turns a weekly weight-loss goal into the daily deficit and target intake needed to reach it.
Health
Calorie Deficit Calculator
Estimate target intake, deficit and weekly weight change from energy balance.
Calculator
About this calculator
Formula notes
A 0.5 kg/week goal ≈ 550 kcal/day deficit (using ≈7700 kcal per kg of body fat); target intake = maintenance − deficit.
Worked examples
- Example: maintenance 2400 kcal with a 0.5 kg/week goal needs about a 550 kcal deficit, so roughly 1850 kcal/day.
- A 500 kcal nominal daily deficit totals 3,500 kcal in 7 days, but it does not guarantee a fixed amount of fat loss because expenditure and water balance change.
How to use it
- Enter your maintenance calories (or estimate with the TDEE tool).
- Enter the weekly loss goal.
- Read the daily deficit and target intake.
Frequently asked questions
Is 7700 kcal per kg exact?
It is an approximation for fat tissue; real loss includes water and lean mass, so results vary.
How big a deficit is safe?
Most guidance suggests 0.25–1 kg/week; very large deficits risk muscle loss and rebound.
Limits and interpretation
- Linear calorie-to-weight rules oversimplify metabolic adaptation, water shifts, adherence, and changing energy needs.
- Aggressive targets can be inappropriate, especially during pregnancy, growth, illness, eating-disorder recovery, or high training loads.