Formula
The old Wishnofsky rule is about 3,500 kcal per pound, close to 7,700 kcal per kilogram. Days follow from that rough store:
Days = kilograms × 7,700 / daily deficit
The daily target is maintenance minus the deficit. Real weight change is not a fixed store of energy, so the day count is a planning sketch.
Assumptions
- The maintenance number is one you already estimated or measured.
- Every day uses the same deficit.
- One kilogram is treated as 7,700 kcal.
Worked example
A 500 kcal gap from 2,000 kcal estimates 30.8 days for 2 kg.
Input definitions
- Daily deficit
- How far below maintenance the day is planned.
- Kilograms to change
- The weight difference you are sketching, not a promise.
Limitations
This is an informational estimate for adults. It is not a diagnosis, a diet plan, or a training prescription. Pregnancy, illness, and medication can change what is appropriate.
Questions
Will the scale follow this day count?
Not exactly. Water, composition, and adaptation move the scale off a fixed 7,700 kcal rule.
Where does maintenance come from?
Type a number you already have. The calorie page and the TDEE page estimate maintenance with two different equations.