Reference formulas and worked examples below keep their stated units. Monetary examples use USD; dimensional examples use US customary units unless labeled otherwise. Metric calculator inputs are converted to these reference units before calculation. Choosing another currency does not convert example amounts or exchange money.
How to use this calorie deficit calculator
Enter an estimated maintenance level, then choose a percentage reduction, a calorie reduction or an intake to compare. Other days in the week use the maintenance amount.
How the calculation works
Percentage mode: daily reduction = maintenance × percentage/100; modeled intake = maintenance − reduction. Calorie-reduction mode subtracts the chosen amount directly.
Intake-comparison mode: daily gap = maintenance − entered intake. Positive is a deficit; negative is a surplus.
Weekly gap = daily gap × selected days. Weekly intake combines those days at the selected intake with remaining days at maintenance. No fixed calories-per-pound rule is used to forecast weight change.
Worked example
With estimated maintenance of 2,400 kcal/day and a chosen 10% reduction, modeled intake is 2,160 and the daily gap is 240. Applied five days per week with the other two at maintenance, the weekly gap is 1,200 kcal and average intake is about 2,229 kcal/day.
Limits and assumptions
Adult arithmetic only; not for children, pregnancy, breastfeeding or condition-specific nutrition planning. This general tool does not generate intake below 1,200 kcal/day; that product limit does not establish that a higher intake is adequate for any individual. Maintenance estimates and energy needs change; no metabolic adaptation, weight trajectory or safe target is calculated.
Frequently asked questions
Does this tell me when I will reach a weight goal?
No. Weight change is not a constant conversion from calories to kilograms. This page reports energy arithmetic only.
Where can I estimate maintenance energy?
The related TDEE calculator supplies a resting-plus-activity scenario. Actual maintenance needs may differ; this page accepts your chosen estimate.
What happens if intake is above maintenance?
Intake-comparison mode reports a surplus instead of labeling it a deficit.
Does the 1,200 kcal limit mean that amount is safe for me?
No. It is only a boundary of this general tool. Individual needs can be higher and require appropriate guidance.