Basal Metabolic Rate (BMR) Calculator
Enter your details to see the calories you burn at rest and your total daily needs for your activity level.
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This tool is for information only and does not replace a dietitian or doctor. Talk to one about a personal diet or health programme. The formulas are based on average populations; individual differences can shift the result by ±15%.
How Is BMR Calculated? Harris-Benedict Formula
Basal Metabolic Rate (BMR) is the minimum energy your body needs at complete rest and in a fasted state to keep vital functions such as breathing, heartbeat, body temperature and cell renewal going. The energy used to digest food (the thermic effect of food, TEF) is not part of BMR; it is added on top in your daily expenditure. The calculation uses age, sex, height and weight. Men and women have different muscle-to-fat ratios, so each has its own formula. This tool uses both of the widely accepted equations, Harris-Benedict and Mifflin-St Jeor.
Factors That Affect Metabolism
More muscle means a higher basal metabolic rate, because muscle cells burn more energy at rest than fat cells. BMR usually falls with age. Genetics, hormone status (such as thyroid) and body temperature also affect how much energy you use.
Calculation Formulas
| Formula | Equation | Year |
|---|---|---|
| Mifflin-St Jeor (Male) | 10 × weight + 6.25 × height − 5 × age + 5 | 1990 |
| Mifflin-St Jeor (Female) | 10 × weight + 6.25 × height − 5 × age − 161 | 1990 |
| Harris-Benedict (Male) | 13.397 × weight + 4.799 × height − 5.677 × age + 88.36 | 1984 |
| Harris-Benedict (Female) | 9.247 × weight + 3.098 × height − 4.330 × age + 447.59 | 1984 |
* Height in cm, weight in kg. Mifflin-St Jeor is currently considered the most accurate method.
How Do You Use Your BMR Value?
If you want to lose weight, keep your total calorie intake above your BMR (extreme restriction slows metabolism). The recommended approach is to multiply BMR by an activity multiplier to get your Total Daily Energy Expenditure (TDEE), then eat 15–20% below that.
Activity Multipliers (TDEE)
Sedentary
Desk job, no daily exercise
Lightly Active
Light exercise 1–3 days/week
Moderately Active
Moderate exercise 3–5 days/week
Very Active
Hard training 6–7 days/week
Extra Active
Physical job and intense training every day