Weight Goal Calculator (Loss & Gain)
Calculate calorie deficits for weight loss or surplus for muscle gain. Features a dynamic timeline comparison between aggressive and sustainable approaches.
About
Effective body weight management relies on the thermodynamic principle of energy balance: Calories In versus Calories Out (CICO). This tool utilizes the Mifflin-St Jeor equation, widely regarded as the most accurate standard for determining Resting Metabolic Rate (RMR) and Total Daily Energy Expenditure (TDEE) in clinical settings.
Unlike generic calculators, this system evaluates the safety of the proposed pace. Rapid weight manipulation often leads to muscle loss (during cuts) or excessive fat accumulation (during bulks). The visualizer below delineates a "Sustainable" path (prioritizing long-term adherence and health) versus an "Aggressive" path, allowing users to manage expectations realistically.
Formulas
The core calculation determines TDEE, then adjusts for the goal.
Where W is weight (kg), H is height (cm), and A is age (years).
Reference Data
| Activity Level | Multiplier Factor | Description |
|---|---|---|
| Sedentary | 1.2 | Desk job, little to no exercise. |
| Lightly Active | 1.375 | Light exercise 1-3 days/week. |
| Moderately Active | 1.55 | Moderate exercise 3-5 days/week. |
| Very Active | 1.725 | Hard exercise 6-7 days/week. |