How many calories does your body burn just by being alive? That's your BMR. Add your activity level to get your TDEE for weight loss, gain, or maintenance.
BMR (Basal Metabolic Rate) is the calories your body burns at complete rest to maintain vital functions like breathing and cell production. TDEE (Total Daily Energy Expenditure) is BMR multiplied by an activity factor that accounts for daily movement and exercise. TDEE is always higher than BMR — typically 1.2 to 1.9 times BMR depending on activity level.
| Aspect | BMR | TDEE |
|---|---|---|
| Full name | Basal Metabolic Rate | Total Daily Energy Expenditure |
| What it measures | Calories at complete rest | Calories including all daily activity |
| Formula (Mifflin-St Jeor) | 10×weight(kg) + 6.25×height(cm) - 5×age + 5 | BMR × Activity Multiplier |
| Typical value (70kg male) | 1,680 kcal | 2,016–3,192 kcal |
| Used for | Understanding baseline metabolism | Setting daily calorie targets |
| For weight loss | Not directly useful | Eat 300-500 kcal below TDEE |
| For muscle gain | Not directly useful | Eat 200-400 kcal above TDEE |
| Activity Level | Multiplier | Example TDEE (BMR=1680) |
|---|---|---|
| Sedentary (desk job, no exercise) | 1.2 | 2,016 kcal |
| Light (exercise 1-3 days/week) | 1.375 | 2,310 kcal |
| Moderate (exercise 3-5 days/week) | 1.55 | 2,604 kcal |
| Active (exercise 6-7 days/week) | 1.725 | 2,898 kcal |
| Very Active (hard exercise + physical job) | 1.9 | 3,192 kcal |
A 30-year-old male, 175 cm tall, weighing 75 kg, exercising 4 times per week: • BMR = 10×75 + 6.25×175 - 5×30 + 5 = 1,724 kcal • Activity multiplier (moderate) = 1.55 • TDEE = 1,724 × 1.55 = 2,672 kcal • For weight loss: 2,672 - 500 = 2,172 kcal/day • For muscle gain: 2,672 + 300 = 2,972 kcal/day
Use BMR to understand your metabolic baseline, but always use TDEE for setting daily calorie targets. Eating below BMR is not recommended as it can slow metabolism and cause muscle loss.
Several formulas exist for estimating BMR, with the Mifflin-St Jeor equation (1990) being the most accurate for the general population. The older Harris-Benedict formula (1919) tends to overestimate BMR by 5-10%. Here is how they compare across different body types.
| Formula | Year | Accuracy | Best For | Limitation |
|---|---|---|---|---|
| Mifflin-St Jeor | 1990 | ±10% (most accurate) | General population | Less accurate for very obese individuals |
| Harris-Benedict (Revised) | 1984 | ±15% | Historical comparison | Tends to overestimate by 5-10% |
| Katch-McArdle | 1996 | ±8% (if BF% is known) | Athletes, lean individuals | Requires accurate body fat % |
| Cunningham | 1980 | ±8% (if LBM is known) | Very active individuals | Requires lean body mass measurement |
| Oxford | 1995 | ±12% | European populations | Less validated for non-European groups |
For most people, the Mifflin-St Jeor equation (used in this calculator) provides the most reliable BMR estimate without needing body composition data. If you know your body fat percentage, the Katch-McArdle formula can be more accurate. Use BMR as a baseline — always base your actual calorie targets on TDEE, not BMR.
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