How Many Calories Do You Need a Day? The TDEE Method
Estimate your daily calorie needs with the TDEE method: BMR formula, activity multipliers, and how to adjust for losing or gaining weight.
"How many calories should I eat?" has a two-step answer: estimate how much energy your body burns in a typical day — your Total Daily Energy Expenditure (TDEE) — then adjust that number up or down depending on your goal. No generic figure like "2,000 calories" fits everyone; a small sedentary adult and a tall active one can differ by well over a thousand calories a day.
Step 1 — Estimate your BMR
Your Basal Metabolic Rate is the energy your body uses at complete rest — breathing, circulation, cell repair. The most widely validated estimate is the Mifflin-St Jeor equation:
- Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
- Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
*Example:* a 30-year-old woman, 165 cm, 68 kg: BMR = 10(68) + 6.25(165) − 5(30) − 161 = 680 + 1,031 − 150 − 161 = 1,400 kcal/day
You can compute yours directly with the BMR Calculator.
Step 2 — Multiply by an activity factor
BMR is only your at-rest burn. TDEE scales it by how much you move:
| Activity level | Multiplier | Typical pattern |
|---|---|---|
| Sedentary | 1.2 | Desk job, little exercise |
| Lightly active | 1.375 | Exercise 1–3 days/week |
| Moderately active | 1.55 | Exercise 3–5 days/week |
| Very active | 1.725 | Hard exercise 6–7 days/week |
| Extremely active | 1.9 | Physical job + daily training |
Our example, moderately active: 1,400 × 1.55 ≈ 2,170 kcal/day. That's her maintenance intake — eat that consistently and weight stays roughly stable.
Most people overestimate their activity level. If you sit most of the day and train three times a week, "lightly active" is usually closer to reality than "moderately active." When in doubt, pick the lower tier and adjust based on results.
Step 3 — Adjust for your goal
- Lose weight: subtract 250–500 kcal from TDEE. A 500 kcal daily deficit corresponds to roughly 0.5 kg (1 lb) per week — a pace most people can sustain.
- Gain muscle: add 250–350 kcal, paired with resistance training. Larger surpluses mostly add fat.
- Maintain: eat at TDEE.
Avoid aggressive cuts below your BMR for extended periods; they're hard to sustain and make it difficult to get adequate protein and micronutrients.
Why the number is a starting point, not a verdict
Every formula carries a margin of error of roughly ±10%, and your true expenditure shifts with muscle mass, sleep, stress, and how much you fidget. Treat the calculated TDEE as a hypothesis: eat at that level for two to three weeks, track your weight trend (not daily fluctuations), and adjust by 100–200 kcal if the trend disagrees with your goal. The Calorie (TDEE) Calculator runs the full calculation — Mifflin-St Jeor plus activity factor and goal adjustment — in one pass, and pairs naturally with a BMI check for context.
FAQ
Is 1,200 calories a day safe? For most adults it's an aggressive floor that makes adequate nutrition difficult, and below many people's BMR. Sustainable deficits are moderate ones; if you're considering very low intakes, involve a physician or registered dietitian.
Do I burn calories doing nothing? Yes — BMR typically accounts for 60–70% of total daily burn. Digestion adds roughly another 10%, and physical activity covers the rest.
Why did my weight loss stall at the same calories? As body weight drops, TDEE drops with it — a lighter body costs less energy to run. Recalculate every 5 kg or so, or whenever a plateau lasts more than three weeks.
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*This article is general information, not medical advice. For personalized guidance — especially with any health condition — consult a healthcare professional. Run your own numbers with the free TDEE Calculator.*
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