Weight Management
Predicted weight change
Applies the common approximation that 3500 kcal corresponds to about one pound of body fat. The result is a linear estimate, not a guarantee.
The Formula
Pounds lost = deficit x days / 3500
Applies the common approximation that 3500 kcal corresponds to about one pound of body fat. The result is a linear estimate, not a guarantee.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| t | Days the deficit is held | days | Assumes the same deficit every day, which is rarely exact in practice. |
| 3500 | Energy per pound of fat | kilocalories per pound | About 3500 kcal per pound; the model treats it as a fixed constant. |
| P | Predicted pounds lost | pounds | The model's linear output over the chosen span. |
What Each Symbol Means
tdays
Days the deficit is held
Assumes the same deficit every day, which is rarely exact in practice.
3500kilocalories per pound
Energy per pound of fat
About 3500 kcal per pound; the model treats it as a fixed constant.
Ppounds
Predicted pounds lost
The model's linear output over the chosen span.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate a calorie deficit page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate A Calorie Deficit, filed under Health. Every number the guide produces comes from substituting into this one line.