BMI & TDEE Calculator
Dual-purpose diet planning tool. Calculates your current Body Mass Index and the Total Daily Energy Expenditure (calories) needed to cut, bulk, or maintain.
About
Effective diet planning requires two baselines: your current health status (BMI) and your energy requirements (TDEE). While BMI identifies if you need to change your weight, TDEE (Total Daily Energy Expenditure) tells you how to do it mathematically.
This tool uses the Mifflin-St Jeor equation, widely considered the most accurate for modern populations, to estimate your Basal Metabolic Rate (BMR). It then applies activity multipliers to derive your maintenance calories. From there, it calculates specific caloric budgets for safe weight loss (typically a 500kcal deficit) or muscle gain.
Formulas
First, BMR is calculated using Mifflin-St Jeor:
Total Daily Energy Expenditure is derived by applying the activity factor:
Reference Data
| Activity Level | Multiplier | Lifestyle Description |
|---|---|---|
| Sedentary | 1.2 | Office job, little to no exercise |
| Lightly Active | 1.375 | Light exercise/sports 1-3 days/week |
| Moderately Active | 1.55 | Moderate exercise/sports 3-5 days/week |
| Very Active | 1.725 | Hard exercise/sports 6-7 days/week |
| Extra Active | 1.9 | Very hard exercise or physical job |