BMR Calculator
Estimate how many calories your body needs each day at complete rest based on your age, sex, height, and weight.
This is the estimated amount of energy your body may use during 24 hours of complete rest.
What Is BMR?
BMR stands for Basal Metabolic Rate. It is an estimate of the number of calories your body needs each day simply to keep essential processes working while you are completely at rest.
Even when you are not exercising, your body continuously uses energy for breathing, circulation, brain activity, temperature regulation, cell repair, digestion-related processes, and normal organ function.
Your BMR therefore represents a large part of your total daily energy use, but it is not the same as the total number of calories you burn during an ordinary day.
Why BMR Matters After Age 50
Understanding your approximate energy needs can become particularly useful as you get older. Body composition, activity levels, muscle mass, sleep, lifestyle, and other factors may change with age.
Because muscle tissue requires energy to maintain, changes in muscle mass can influence how much energy your body uses each day. This is one reason resistance training, regular movement, adequate protein, and balanced nutrition are commonly emphasized as part of healthy aging.
Your BMR should not be treated as a strict calorie target. Instead, use it as one piece of information when thinking about nutrition, weight management, and daily energy requirements.
How Is BMR Calculated?
This calculator uses the widely used Mifflin-St Jeor equation.
For Men
BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
For Women
BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
If you enter your measurements in pounds, feet, and inches, the calculator automatically converts them before applying the formula.
BMR vs. Daily Calorie Needs
One of the most important distinctions to understand is that BMR is not your total daily calorie requirement.
Your body usually burns additional calories through everyday movement, exercise, work, household tasks, walking, digestion, and other physical activity.
When BMR is adjusted according to activity level, the resulting estimate is often referred to as Total Daily Energy Expenditure (TDEE).
| Measurement | What It Estimates |
|---|---|
| BMR | Calories your body needs for essential functions at rest. |
| TDEE | Approximate total calories burned throughout an average day. |
How to Use Your BMR Result
Your calculated BMR can be used as a starting point for understanding your energy needs. However, you generally should not assume that your BMR is the exact number of calories you should eat each day.
Calculate Your BMR
Enter your age, sex, height, and weight to estimate your resting energy requirements.
Consider Your Activity
Daily walking, exercise, work, and other movement increase your energy expenditure above your BMR.
Track Real-World Progress
Your actual body-weight trend, energy levels, nutrition, and health needs are more useful than relying on one calculated number alone.
What Factors Can Affect Your BMR?
BMR equations provide estimates. Two people of the same age, height, weight, and sex can still have different real-world metabolic rates.
- Age: Energy requirements may change as the body ages.
- Body composition: Muscle and fat tissue have different energy requirements.
- Body size: Larger bodies generally require more energy to maintain.
- Genetics: Individual biological differences can influence metabolism.
- Hormonal factors: Thyroid and other hormones can affect metabolic rate.
- Health conditions: Certain illnesses or medications may influence energy requirements.
- Dieting history: Significant or prolonged calorie restriction may affect energy use.
Can You Increase Your Metabolism After 50?
There is no reliable shortcut that dramatically increases metabolism, but several healthy habits can support body composition and overall energy expenditure.
- Perform appropriate resistance or strength training.
- Stay physically active throughout the day.
- Include adequate protein as part of a balanced diet.
- Prioritize consistent, high-quality sleep.
- Avoid unnecessarily severe or prolonged calorie restriction.
- Follow an exercise approach appropriate for your current health and fitness level.
Example BMR Calculation
Consider a 55-year-old man who weighs 75 kg and is 170 cm tall.
BMR = (10 × 75) + (6.25 × 170) − (5 × 55) + 5
BMR = 750 + 1,062.5 − 275 + 5
Estimated BMR ≈ 1,543 calories per dayThis does not mean he should automatically eat exactly 1,543 calories per day. His actual daily energy requirements would normally be higher because ordinary daily activity requires additional energy.
Frequently Asked Questions
Not necessarily. BMR estimates energy used at complete rest. Your actual daily calorie needs also include movement, exercise, digestion, work, and other activities.
A higher or lower BMR is not automatically good or bad. It mainly reflects differences in body size, composition, age, sex, and other individual factors.
Energy requirements can change with age. Changes in activity, body composition, muscle mass, and other health or lifestyle factors may all contribute.
It provides an estimate based on a mathematical equation. Individual metabolic rates can vary, so calculated results should not be interpreted as exact laboratory measurements.
BMR estimates resting energy expenditure, while BMI compares weight with height to provide a general weight-category screening measurement. They measure completely different things.
