BMR Calculator
Estimate the calories your body burns at rest (BMR) and your total daily energy needs (TDEE) with the Mifflin-St Jeor equation. Works in metric or imperial units.
← Back to all toolsLose or gain weight? Get your daily calorie target →Enter your sex, age, height and weight to see your BMR.
What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest — just to keep your heart beating, lungs breathing, and organs working. It is the largest part of your daily energy burn.
How we calculate it
Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161We use the Mifflin-St Jeor equation, the most widely recommended formula for estimating BMR.
Activity levels
Multiply your BMR by an activity factor to estimate the calories you need to maintain your weight (TDEE):
| Activity level | Description | Multiplier |
|---|---|---|
| Sedentary | Little or no exercise, desk job | × 1.2 |
| Lightly active | Light exercise 1–3 days a week | × 1.375 |
| Moderately active | Moderate exercise 3–5 days a week | × 1.55 |
| Very active | Hard exercise 6–7 days a week | × 1.725 |
| Extra active | Physical job or training twice a day | × 1.9 |
Keep in mind
BMR and TDEE are estimates, not exact measurements. Your actual needs also depend on:
- Muscle mass and body composition
- Hormones and metabolic conditions
- Age and genetics
- The thermic effect of food and non-exercise activity
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is the energy your body needs at complete rest. TDEE is your BMR multiplied by an activity factor — the total calories you need to maintain your current weight.
How accurate is the Mifflin-St Jeor equation?
It is one of the most reliable BMR formulas available and is usually within about 10% for most people — but it is still an estimate.
Which activity level should I choose?
Pick the level that matches your typical week: little or no exercise for sedentary, regular training for moderate or active. When unsure, choose the more conservative option.
Can I use BMR to lose weight?
Yes — treat it as a starting point for a calorie budget. Eating below your TDEE generally leads to weight loss, ideally with guidance from a professional.
Does this calculator store my data?
No. All calculations happen locally in your browser. Your inputs are never uploaded or saved.
Is BMR the same for men and women?
Not exactly. At the same height and weight, the formula adds 5 for men and subtracts 161 for women, reflecting common differences in resting metabolism.