Weight Management
Daily calorie deficit
The gap between the energy you use and the energy you take in. A positive result is a deficit; zero or below means no deficit at all.
The Formula
Deficit = maintenance calories - intake calories
The gap between the energy you use and the energy you take in. A positive result is a deficit; zero or below means no deficit at all.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| M | Maintenance calories (TDEE) | kilocalories | Total daily energy expenditure. An estimate that falls as body weight falls. |
| I | Calories eaten | kilocalories | Planned or actual daily intake. It must be below maintenance for a deficit to exist. |
| D | Daily deficit | kilocalories | Positive when intake sits below maintenance, negative otherwise. |
What Each Symbol Means
Mkilocalories
Maintenance calories (TDEE)
Total daily energy expenditure. An estimate that falls as body weight falls.
Ikilocalories
Calories eaten
Planned or actual daily intake. It must be below maintenance for a deficit to exist.
Dkilocalories
Daily deficit
Positive when intake sits below maintenance, negative otherwise.
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.