Calorie Deficit Calculator
Turn an existing maintenance-calorie estimate into a simple intake target and cumulative energy plan. The calculator does not convert the deficit into promised weight loss because real body-weight change is dynamic.
Arithmetic planning only for adults. It does not recommend a safe deficit, predict weight loss, account for metabolic adaptation, or replace medical or dietetic care. Following the NIDDK planner's adult safeguard, this tool will not calculate a target below 1,000 kcal/day. It is not for people under 18, pregnant or breastfeeding people, or anyone whose clinician advises against calorie restriction.
Enter your scenario
Use the details that match your situation. Your estimate stays in this browser.
How this estimate works
- The daily intake target equals entered maintenance calories minus the chosen deficit; the calculator rejects a result below 1,000 kcal/day instead of presenting it as a usable target.
- The cumulative planned deficit equals daily deficit multiplied by plan days.
- No fixed calories-to-weight conversion is shown because the National Institutes of Health models body-weight change as dynamic rather than perfectly linear.
Official sources
- NIDDK: Body Weight Planner and adult-use limitations
- National Academies dietary reference material: adult energy-expenditure equations
Rules and published amounts can change. Open the source pages and confirm the date and conditions before making a tax, payroll, benefits, pension, or investment decision.
Frequently asked questions
Does this predict how much weight I will lose?
No. It calculates an energy plan only; actual weight change is dynamic and differs by person and over time.
Is the displayed intake target automatically safe?
No. The calculator blocks targets below 1,000 kcal/day in line with the NIDDK planner's adult floor, but any displayed arithmetic result is still not a recommendation. Consult a qualified clinician or dietitian for individual safety.