Calculate TDEE from BMR and activity level. Set a deficit (500 kcal below) for fat loss or a surplus (300-500 kcal above) for muscle gain. Daily targets.
Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a 24-hour period. It is the sum of your Basal Metabolic Rate (BMR), which accounts for 60-75% of total energy use, the Thermic Effect of Food (TEF) at about 10%, and physical activity, which is the most variable component. Knowing your TDEE is the starting point for any body composition goal, because weight changes only when calorie intake differs from TDEE.
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) explains that a sustained calorie deficit of 3,500 calories produces roughly 1 pound of fat loss, though this relationship is not perfectly linear over time. A deficit of 400-500 calories per day typically produces 0.3-0.5 kg (0.7-1 lb) of weight loss per week, which is the recommended safe rate according to the Academy of Nutrition and Dietetics.
The Mifflin-St Jeor equation, endorsed by the Academy of Nutrition and Dietetics in its 2005 evidence review, is the most accurate BMR prediction formula for the general population. It takes weight, height, age, and sex into account:
BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age + s
Where s = +5 for men and -161 for women. For a 35-year-old man who is 5 ft 10 in (178 cm) and weighs 175 lb (79.5 kg): BMR = 10 × 79.5 + 6.25 × 178 - 5 × 35 + 5 = 795 + 1,112.5 - 175 + 5 = 1,737.5 calories per day. This is the energy he burns at complete rest, before any activity.
| Activity Level | Multiplier | TDEE (BMR 1,738) |
|---|---|---|
| Sedentary (desk job, no exercise) | 1.2 | 2,086 |
| Lightly active (1-3 days/week) | 1.375 | 2,390 |
| Moderately active (3-5 days/week) | 1.55 | 2,694 |
| Very active (6-7 days/week) | 1.725 | 2,998 |
| Extra active (physical job + training) | 1.9 | 3,302 |
Once your TDEE is known, adjusting your calorie intake for your goal is straightforward. For fat loss (cutting), subtract 400-500 calories from your TDEE. This produces a deficit of roughly 0.3-0.5 kg (0.7-1 lb) of weight loss per week, which the NIDDK and the American College of Sports Medicine (ACSM) recommend as a safe, sustainable rate. For the example man with a TDEE of 2,694 (moderately active), a cutting target is 2,194-2,294 calories per day.
For muscle gain (bulking), add 250-500 calories above TDEE. A surplus of 250 calories per day produces slow, lean gains with minimal fat accumulation, while 500 calories per day supports faster muscle growth but adds more body fat. For maintenance, eat exactly at TDEE and adjust based on weekly weight trends. The key is to track your weight weekly and adjust intake by 100-200 calories if the scale moves faster or slower than your target rate of 0.3-0.5 kg per week.
TDEE Calculator — Calories for Cut, Bulk & Maintain
Put the numbers from this guide to work. The calculation runs entirely in your browser — nothing is sent to a server.