How it works
Your daily maintenance calories hinge on a single multiplier. The TDEE Calculator computes resting metabolism (BMR) via the Mifflin-St Jeor equation, then scales that figure by an activity factor to reflect how much you actually move in a day. The output is total daily energy expenditure — the calorie target where weight stays stable.
The activity multiplier is what separates this calculation from a raw BMR figure. Five tiers map to lifestyle intensity, ranging from 1.2 for sedentary desk work up to 1.9 for heavy daily training or a physical job. Because daily movement drives the final number, two people with identical height, weight, and age can land on very different maintenance calories depending on activity.
The formula
TDEE = BMR × activity_factor
BMR uses the Mifflin-St Jeor equations:
- Male:
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 - Female:
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
| Activity level | Factor |
|---|---|
| Sedentary (little/no exercise) | 1.2 |
| Light (1–3 days/week) | 1.375 |
| Moderate (3–5 days/week) | 1.55 |
| Active (6–7 days/week) | 1.725 |
| Very active (hard daily / physical job) | 1.9 |
Worked example
Take a 30-year-old male, 80 kg, 178 cm, training 4 days per week (moderate activity, factor 1.55).
Step 1 — BMR:
10 × 80 + 6.25 × 178 − 5 × 30 + 5 = 800 + 1112.5 − 150 + 5 = 1767.5 kcal
Step 2 — TDEE:
1767.5 × 1.55 = 2740 kcal (rounded). That is the maintenance target.
Step 3 — Macronutrient split. A common starting ratio for someone training moderately is 30% protein, 40% carbohydrate, 30% fat. Applied to 2740 kcal:
- Protein: 2740 × 0.30 = 822 kcal → 822 ÷ 4 = 206 g protein
- Carbs: 2740 × 0.40 = 1096 kcal → 1096 ÷ 4 = 274 g carbs
- Fat: 2740 × 0.30 = 822 kcal → 822 ÷ 9 = 91 g fat
| Macro | % of calories | Calories | Grams |
|---|---|---|---|
| Protein | 30% | 822 | 206 g |
| Carbohydrate | 40% | 1096 | 274 g |
| Fat | 30% | 822 | 91 g |
| Total | 100% | 2740 | — |
This breakdown matters because two identical 2740-kcal days can feel and perform very differently depending on where the calories come from. The protein target supports muscle repair across four training sessions weekly. The carbohydrate allocation fuels moderate-to-intense workouts and replenishes glycogen. The fat portion covers essential hormone and cell-membrane functions. Adjust ratios based on recovery, hunger, and performance rather than chasing a perfect number.
Things to watch
Activity factors are blunt instruments. A 1.55 multiplier assumes a consistent 3–5 exercise days alongside ordinary daily movement. If you train hard but sit for ten hours, true expenditure may trend lower. Conversely, a physical job plus gym sessions can push real burn above 1.725. Track intake against weight trends for two to three weeks, then adjust the calorie target by 100–150 kcal if weight drifts. TDEE output is an estimate, not professional advice — consult a registered dietitian for clinical guidance.