Calculate Your BMR
Your BMR Results
Basal Metabolic Rate (BMR)
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calories/day
Daily Calorie Needs
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calories/day
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Understanding Your Basal Metabolic Rate (BMR)
Your Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions like breathing, circulation, and cell production while at complete rest. Essentially, it's the number of calories you would burn if you stayed in bed all day.
How BMR is Calculated
This calculator uses the Mifflin-St Jeor equation, which is considered one of the most accurate BMR formulas:
For Men: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(y) + 5
For Women: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(y) - 161
Example: A 35-year-old woman who weighs 68 kg and is 165 cm tall would have a BMR of:
(10 × 68) + (6.25 × 165) - (5 × 35) - 161 = 1,387 calories/day
Daily Calorie Needs
To estimate your total daily calorie needs, we multiply your BMR by an activity factor:
- Sedentary (little to no exercise): BMR × 1.2
- Lightly active (light exercise 1-3 days/week): BMR × 1.375
- Moderately active (moderate exercise 3-5 days/week): BMR × 1.55
- Very active (hard exercise 6-7 days/week): BMR × 1.725
- Extremely active (very hard exercise, physical job): BMR × 1.9
Frequently Asked Questions
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest, while TDEE (Total Daily Energy Expenditure) includes all calories burned through daily activities and exercise. TDEE is typically higher than BMR.
Why does BMR decrease with age?
As we age, we tend to lose muscle mass and our metabolic processes slow down. This natural decline in muscle mass (sarcopenia) reduces the number of calories our bodies burn at rest.
Can I increase my BMR?
Yes, you can increase your BMR by building muscle through strength training, as muscle tissue burns more calories at rest than fat tissue. Staying hydrated, getting enough sleep, and eating adequate protein can also support a healthy metabolism.
How accurate is the Mifflin-St Jeor equation?
The Mifflin-St Jeor equation is considered one of the most accurate BMR formulas for the general population, with an accuracy of about ±10%. However, individual variations in body composition, genetics, and health conditions can affect actual metabolic rate.
Should I eat below my BMR to lose weight?
It's generally not recommended to consistently eat below your BMR, as this can signal to your body that it's in starvation mode, potentially slowing your metabolism. A safer approach is to create a modest calorie deficit based on your TDEE (typically 300-500 calories less than TDEE).