Estimate your Total Daily Energy Expenditure (TDEE) — the calories or kilojoules you burn in a typical day — from age, sex, height, weight, and activity. Switch US and metric units, pick Calories or Kilojoules, and see BMI plus calorie targets to lose or gain weight at a steady pace.
What TDEE includes
BMR is most of a typical day's burn (often around 60–70%). Activity covers both planned exercise and NEAT (non-exercise activity thermogenesis). The thermic effect of food — energy used to digest what you eat, sometimes estimated around 10% of intake — is not added as a separate multiplier here; it is absorbed into the BMR × activity estimate.
BMI categories for adults
| BMI (kg/m²) | Category |
|---|---|
| Below 16 | Severe Thinness |
| 16 – 17 | Moderate Thinness |
| 17 – 18.5 | Mild Thinness |
| 18.5 – 25 | Normal |
| 25 – 30 | Overweight |
| 30 – 35 | Obese Class I |
| 35 – 40 | Obese Class II |
| 40 and above | Obese Class III |
Examples
Man, 25, 5 ft 10 in, 165 lb, moderate activity
Mifflin St Jeor BMR is about 1,740 calories. At the moderate factor (1.465) TDEE is 2,549 Calories/day (BMI 23.7, Normal). Mild / standard / extreme loss targets are 2,299, 2,049, and 1,549 Calories/day (about 90%, 80%, and 61% of TDEE); the matching gains are 2,799, 3,049, and 3,549.
Same person in kilojoules
Those calorie figures convert at 4.184 kJ per calorie, so TDEE is 10,665 kJ/day, with loss targets 9,619 / 8,573 / 6,481 and gains 11,711 / 12,757 / 14,849 kJ/day.
Woman, 32, 170 cm, 70 kg, extra active
Female Mifflin St Jeor at extra-active 1.9 gives TDEE 2,739 Calories/day and BMI 24.2. Loss targets are 2,489 / 2,239 / 1,739; gains are 2,989 / 3,239 / 3,739.
Formula
TDEE starts with basal metabolic rate (BMR), then multiplies by an activity factor. Mifflin St Jeor (the default) uses kilograms (W), centimetres (H), and years (A). Katch-McArdle uses lean mass from body-fat fraction (bf):
Men: BMR = 10W + 6.25H − 5A + 5
Women: BMR = 10W + 6.25H − 5A − 161
Katch: BMR = 370 + 21.6 × W × (1 − bf)
TDEE = BMR × activity factor
Kilojoules are round(calories × 4.184) after calories are rounded to whole
numbers. BMI is weight (kg) ÷ height (m)², shown to one decimal.
| Activity level | Factor |
|---|---|
| Basal Metabolic Rate (BMR) | 1.0 |
| Sedentary (little or no exercise) | 1.2 |
| Light (1–3 times/week) | 1.375 |
| Moderate (4–5 times/week) | 1.465 |
| Active (daily, or intense 3–4 times/week) | 1.55 |
| Very Active (intense 6–7 times/week) | 1.725 |
| Extra Active (very intense daily, or physical job) | 1.9 |
Weight-goal rows apply fixed ±250, ±500, and ±1,000 calorie adjustments. Their pace labels are conventional planning shorthand, not outcome promises.
Loss targets below 1,500 calories/day are hidden. Do not eat that little without medical guidance, and avoid losing more than about 2 lb (1 kg) per week.
Exercise here means 15–30 minutes of elevated heart rate. Intense exercise is 45–120 minutes; very intense is 2+ hours. Activity also includes a physical job and everyday non-exercise movement.
Sources
- Mifflin et al. (1990) — resting-energy equation and study population.
- NIDDK Body Weight Planner research — dynamic changes in metabolism and expenditure.
Understand the resting estimate first
The BMR Calculator compares resting-energy equations before activity is included. BMR is not a daily food target by itself. Use the difference between the resting estimate and TDEE to understand the activity assumption, rather than treating either prediction as a measurement of your personal energy needs.