What is Basal Metabolic Rate (BMR)?
Your Basal Metabolic Rate (BMR) is the total number of calories your body requires to perform basic, life-sustaining functions while completely at rest. Even when you are sleeping or sitting on the couch doing absolutely nothing, your body is working hard to keep you alive. These essential functions include breathing, circulating blood, controlling body temperature, cellular growth, and neurological function.
For most individuals, BMR accounts for roughly 60% to 75% of their Total Daily Energy Expenditure (TDEE).
BMR vs. TDEE: What's the Difference?
It is very common to confuse BMR with TDEE. Here is the simple difference:
- BMR (Basal Metabolic Rate): The calories you burn if you stayed in bed all day and did not move.
- TDEE (Total Daily Energy Expenditure): Your BMR plus the calories you burn from daily movement, working, digesting food, and exercising.
If you want to know how many calories you should eat to lose weight, you should calculate your TDEE using our Calorie Calculator. BMR is simply the foundational baseline.
How is BMR Calculated?
This calculator uses the Mifflin-St Jeor equation, which is currently widely considered the most accurate formula for calculating BMR in healthy adults by the medical and fitness community.
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161
Frequently Asked Questions (FAQ)
1. Does my BMR decrease as I get older?
Yes. As human beings age, we naturally lose lean muscle mass, and our metabolic rate slows down. Because muscle tissue requires more calories to maintain than fat tissue, a decrease in muscle means your body requires fewer calories at rest. This is why people often gain weight as they age if they do not adjust their diet or exercise habits.
2. How can I increase my BMR?
The single most effective way to increase your Basal Metabolic Rate is to build more lean muscle mass through resistance training and weightlifting. Muscle is highly metabolically active, meaning your body has to burn more calories just to maintain it, even when you are resting.
3. Is it dangerous to eat fewer calories than my BMR?
Yes. Medical professionals generally strongly advise against consuming fewer calories than your BMR. Eating below your BMR deprives your body of the basic energy it needs to sustain vital organ functions. This can lead to a severely depressed metabolism, muscle loss, hair loss, fatigue, and nutritional deficiencies.