BMR & Calorie Calculator
Calculate your Basal Metabolic Rate and daily calorie needs to achieve your health goals
Your Information
Activity Level
Your Results
Calories per day at rest
Daily Calorie Needs
| Activity Level | Calories |
|---|---|
| Sedentary | 2,058 |
| Lightly Active | 2,358 |
| Moderately Active | 2,658 |
| Very Active | 2,958 |
| Extra Active | 3,259 |
Note: BMR is the number of calories your body needs to perform basic life-sustaining functions. These results are estimates based on the Mifflin-St Jeor Equation, which is considered the most accurate for calculating BMR.
What Is Basal Metabolic Rate (BMR)?
Basal Metabolic Rate (BMR) is the amount of energy your body needs to perform basic life-sustaining functions while at complete rest in a neutral temperature environment and with an inactive digestive system. It’s like calculating how much fuel a car consumes while idling.
At this resting state, your body only uses energy to maintain vital functions such as breathing, blood circulation, brain activity, and the operation of organs like the heart, kidneys, liver, and lungs. For most people, BMR accounts for around 70% of daily calorie expenditure, with 20% from physical activity and 10% from digesting food (thermogenesis).
How Is BMR Measured or Estimated?
BMR is ideally measured under very strict conditions — while you’re awake but fully rested and with an inactive sympathetic nervous system. Because of this, it’s often estimated using equations based on statistical data.
Common BMR Equations:
1. Mifflin-St Jeor Equation (Most Accurate for General Use)
Men:
BMR = 10W + 6.25H - 5A + 5Women:
BMR = 10W + 6.25H - 5A - 161
2. Revised Harris-Benedict Equation
Men:
BMR = 13.397W + 4.799H - 5.677A + 88.362Women:
BMR = 9.247W + 3.098H - 4.330A + 447.593
3. Katch-McArdle Formula (Best for Lean Individuals Who Know Their Body Fat %)
BMR = 370 + 21.6 × (1 - F) × W
Where:
W= weight in kgH= height in cmA= age in yearsF= body fat percentage
Factors That Influence BMR
Muscle Mass: More muscle increases BMR since muscle tissue requires more energy at rest.
Age: BMR decreases with age as muscle mass and metabolic activity decline.
Genetics: Hereditary traits affect how efficiently your body burns calories.
Weather: Both cold and hot environments can raise BMR as the body works to maintain internal temperature.
Diet: Regular, balanced meals help sustain BMR. Starvation or extreme dieting can lower it significantly.
Pregnancy & Hormones: Pregnancy increases BMR. Hormonal changes, like during menopause, can also affect it.
Supplements: Stimulants like caffeine can temporarily raise BMR.
BMR vs. RMR
While often used interchangeably, there’s a slight difference:
BMR is measured in strict conditions.
RMR (Resting Metabolic Rate) is similar but measured in more relaxed, less controlled conditions.
Limitations of BMR Calculations
Even with precise formulas and professional tools, BMR is still an estimate. A 2005 meta-analysis found that 26% of BMR variation remains unexplained, even after accounting for all known factors.
That’s why tracking your actual food intake, physical activity, and results (like weight or performance) over time is the most effective way to achieve fitness or health goals. Use BMR as a starting point—but adapt based on real-world results.
Related Calculators:
BMI Calculator, Body Fat Calculator
External Resources:
BMR Calculator on Calculator.net