BMR Calculator - Basal Metabolic Rate Calculator & Daily Calorie Calculator
Free BMR calculator to estimate your basal metabolic rate—the amount of energy expended while at rest in a neutrally temperate environment, and in a post-absorptive state (meaning that the digestive system is inactive, which requires about 12 hours of fasting). Calculate BMR using Mifflin-St Jeor, Harris-Benedict, or Katch-McArdle equations.
Last updated: February 2, 2026
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Ages: 15 - 80
BMR Results
BMR
1,605 Calories/day
Daily calorie needs based on activity level
Exercise: 15-30 minutes of elevated heart rate activity. Intense exercise: 45-120 minutes. Very intense exercise: 2+ hours.
BMR Guidelines:
- • BMR is the energy expended while at rest
- • ~70% of total calories burned daily is from BMR
- • Physical activity makes up ~20% of expenditure
- • These are estimates; individual results may vary
BMR Calculation Equations
For Men:
BMR = 10W + 6.25H - 5A + 5
For Women:
BMR = 10W + 6.25H - 5A - 161
W = weight (kg), H = height (cm), A = age
For Men:
BMR = 13.397W + 4.799H - 5.677A + 88.362
For Women:
BMR = 9.247W + 3.098H - 4.330A + 447.593
W = weight (kg), H = height (cm), A = age
Formula:
BMR = 370 + 21.6(1 - F)W
W = weight (kg), F = body fat %
More accurate for leaner individuals who know their body fat percentage.
Quick Example Result
For a 25-year-old male with height 180 cm and weight 60 kg:
BMR
1,605 Calories/day
Sedentary
1,926 Calories/day
~70% of daily calories come from BMR
How the BMR Calculator Works
The basal metabolic rate (BMR) is the amount of energy needed while resting in a temperate environment when the digestive system is inactive. It is the equivalent of figuring out how much gas an idle car consumes while parked. In such a state, energy will be used only to maintain vital organs, which include the heart, brain, kidneys, nervous system, intestines, liver, lungs, sex organs, muscles, and skin.
Daily Energy Distribution
For most people, upwards of ~70% of total energy (calories) burned each day is due to upkeep. Physical activity makes up ~20% of expenditure and ~10% is used for the digestion of food.
BMR Variables
Several factors influence BMR:
- Muscle Mass: The more muscle mass, the higher the BMR. Anaerobic exercises like weight-lifting build muscle mass, increasing resting energy consumption.
- Age: The more elderly an individual, the lower their BMR, as metabolic processes slow down with age.
- Genetics: Hereditary traits passed down from ancestors influence BMR.
- Weather: Cold environments raise BMR because of energy required to maintain body temperature. BMR increases approximately 7% for every increase of 1.36°F in body temperature.
- Diet: Small, routinely dispersed meals increase BMR. Starvation can reduce BMR by as much as 30%.
- Pregnancy: Ensuring the livelihood of a separate fetus internally increases BMR.
- Supplements: Certain supplements or drugs like caffeine can raise BMR.
Activity Level Multipliers
The daily caloric need is the BMR value multiplied by a factor with a value between 1.2 and 2.0, depending on activity level:
- Sedentary (little or no exercise)BMR × 1.2
- Exercise 1-3 times/weekBMR × 1.375
- Exercise 4-5 times/weekBMR × 1.55
- Daily exercise or intense 3-4 times/weekBMR × 1.725
- Intense exercise 6-7 times/weekBMR × 1.9
- Very intense exercise daily, or physical jobBMR × 2.0
Limitations & Accuracy
A 2005 meta-analysis study on BMR showed that when controlling all factors of metabolic rate, there is still a 26% unknown variance between people. Essentially, an average person eating an average diet will likely have expected BMR values, but there are factors that are still not understood that determines BMR precisely.
Online BMR tests with rigid formulas are not the most accurate method of determining an individual's BMR. It is better to consult a certified specialist or measure BMR through a calorimetry device. However, BMR calculations can aid in laying down the foundations for health and fitness goals.
Sources & References
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. - A new predictive equation for resting energy expenditure in healthy individualsAmerican Journal of Clinical Nutrition, 1990
- Roza AM, Shizgal HM. - The Harris Benedict equation reevaluated: resting energy requirements and the body cell massAmerican Journal of Clinical Nutrition, 1984
- Johnstone AM, Murison SD, Duncan JS, Rance KA, Speakman JR. - Factors influencing variation in basal metabolic rateAmerican Journal of Clinical Nutrition, 2005
Need help with other health calculations? Check out our BMI calculator and calorie calculator.
Get Custom Calculator for Your PlatformBMR Calculator Examples
Input Values:
- Age: 25 years
- Gender: Male
- Height: 180 cm
- Weight: 60 kg
- Equation: Mifflin-St Jeor
Calculation Steps:
- Apply Mifflin-St Jeor formula for men
- BMR = 10W + 6.25H - 5A + 5
- BMR = 10(60) + 6.25(180) - 5(25) + 5
- BMR = 600 + 1,125 - 125 + 5
- BMR = 1,605 Calories/day
Result: BMR = 1,605 Calories/day
Daily calorie needs: Sedentary = 1,926 | Active = 2,488 | Very Active = 3,050
Female Example
30-year-old female, 165 cm, 55 kg
BMR: ~1,300 Calories/day
Katch-McArdle Example
Requires body fat percentage
More accurate for lean individuals
Frequently Asked Questions
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