BMR Calculator
BMI Calculator
TDEE Calculator
This calculator estimates your Basal Metabolic Rate (BMR), which is the number of calories your body burns at rest to maintain vital body functions like breathing, circulation, and cell production. Use it alongside our BMI calculator to get a fuller picture of your health.
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Disclaimer: Whilst every effort has been made in building our calculator tools, we are not to be held liable for any damages or monetary losses arising out of or in connection with their use. Full disclaimer.
How to calculate your BMR
To use this calculator and find your BMR, simply enter your details inside the form at the top of this page.
Our BMR calculator allows you to use either the Mifflin-St Jeor equation (considered the most accurate for most people) or the revised Harris-Benedict equation. Both formulas take into account your sex, age, height, and weight.
Mifflin-St Jeor equation:
Harris-Benedict equation (revised):
Once you have your BMR value, you can estimate your Total Daily Energy Expenditure (TDEE) by multiplying your BMR by an activity factor.
Example BMR calculation
Let's say you are a 35-year-old male, standing 5 ft 10 in tall (177.8 cm) and weighing 176 lbs (79.8 kg). Here's how you'd calculate your BMR:
Using Mifflin-St Jeor:
BMR = (10 × 79.8) + (6.25 × 177.8) − (5 × 35) + 5
BMR = 798 + 1111.25 − 175 + 5
BMR =
1,739 calories/day
Using Harris-Benedict (revised):
BMR = 88.362 + (13.397 × 79.8) + (4.799 × 177.8) − (5.677 × 35)
BMR = 88.362 + 1069.08 + 853.26 − 198.70
BMR =
1,812 calories/day
Multiplying by activity factor:
If the person above is moderately active (exercises 3–5 days/week), the activity multiplier is 1.55:
TDEE (Mifflin-St Jeor):
TDEE = 1,739 × 1.55 =
2,695 calories/day
What is BMR?
Your Basal Metabolic Rate (BMR) is the number of calories your body needs to perform its most basic (basal) life-sustaining functions. These include breathing, circulation, cell production, nutrient processing, protein synthesis, and ion transport. In other words, it's the energy your body uses just to stay alive, even if you spent all day resting in bed.
BMR is the single largest component of your total daily calorie expenditure, typically accounting for 60–75% of your total calories burned each day. The remaining energy is used for physical activity and digesting food (the thermic effect of food).
Total Daily Energy Expenditure (TDEE)
Basal Metabolic RateBMR
+
Physical ActivityPA
+
Thermic Effect of FoodTEF
= TDEE (Total Daily Energy Expenditure)
BMR accounts for approximately 60–75% of your TDEE
It's important to note that your BMR is not the same as your TDEE. It also doesn't tell you how many calories you should consume each day — for that, the activity level needs to be taken into account.
Your BMR can be influenced by many factors including age, sex, body composition, hormonal status, and genetics. Generally, men have a higher BMR than women, and BMR tends to decrease with age as muscle mass declines.
The Mifflin-St Jeor equation is generally considered the most reliable formula for estimating BMR for most people, according to the American Dietetic Association. The Harris-Benedict equation, while still commonly used, tends to overestimate calorie needs by about 5%.
What is the difference between BMR and TDEE?
While BMR measures the calories your body burns at complete rest, TDEE (Total Daily Energy Expenditure) represents the total number of calories your body burns in a day, including all physical activity and digestion.
You can think of BMR as your baseline — the minimum fuel your body needs. TDEE then adds everything else on top: walking, exercising, fidgeting, and even digesting your meals.
To calculate your TDEE, simply multiply your BMR by an activity factor. The commonly used activity multipliers (known as the Harris-Benedict activity factors) are:
| Activity Level | Description | Multiplier |
|---|
| Sedentary | Little or no exercise | 1.2 |
| Lightly active | Light exercise 1–3 days/week | 1.375 |
| Moderately active | Moderate exercise 3–5 days/week | 1.55 |
| Very active | Hard exercise 6–7 days/week | 1.725 |
| Extra active | Very hard exercise or physical job | 1.9 |
The Harris-Benedict equation
The Harris-Benedict equation was first published in 1919 by James Arthur Harris and Francis Gano Benedict. It was revised in 1984 by Roza and Shizgal to improve its accuracy. Our calculator uses this revised version when the Harris-Benedict option is selected.
The Mifflin-St Jeor equation
The Mifflin-St Jeor equation was introduced in 1990 and is now considered more accurate than the Harris-Benedict equation for most people. A 2005 study by the American Dietetic Association found that it was the most reliable method for estimating BMR.
Calculating daily calorie requirements
Use the following steps to calculate how many calories you need per day:
1
Calculate your BMR
Use the calculator at the top of this page to find your Basal Metabolic Rate using either the Mifflin-St Jeor or Harris-Benedict formula.
2
Determine your activity level
Honestly assess how active you are on a daily basis. Most people overestimate their activity level, so be conservative if unsure.
3
Multiply your BMR by your activity factor
This gives you your TDEE — the estimated number of calories you burn per day. To maintain your current weight, consume approximately this many calories.
4
Adjust for your goals
To lose weight, aim for a caloric deficit (consume 500 fewer calories/day to lose ~1 lb/week). To gain weight, add a caloric surplus. Always consult a healthcare professional before making significant dietary changes.
If you have any problems using our BMR calculator, please contact us.